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If you're thinking about implementing Provisioning Services (even if you haven't had a chance to look at the new features yet), investing one hour in this TechTalk will save you that much and more during implementation. This TechTalk will help you to understand how simple it is to implement Provisioning Services and in particular how the new features can make your job easier.
Topics below are the basis for an upcoming TechTalk:
• How are the partitions resized when you build a vDisk with multiple physical/logical drives?
• How does the Offline Database Support work? What features would be enabled in case I can't connect to the Provisioning Services database?
• How can I take advantage of the User Assigned Virtual Disks? Does it work with all vDisk modes?
• How do I configure a LUN to be accessed by multiple PVS Servers without using a network share?
• How can I benefit from the Enhanced Logging to verify what is going on behind the scenes and troubleshoot my environment?
Register now for this TechTalk on Thursday, August 27th at 1PM Eastern standard time.
Elisabeth Teixeira - Principal Engineer - Worldwide Technical Readiness
You can follow me at http://twitter.com/lizteixeira
You can read my blogs at http://community.citrix.com/blogs/citrite/elisabetht
On August 11, 12, and 13 we delivered a Ask the Architect TechTalk series focused on desktop virtualization and VDI. The three part series focused on:
- Deciding between VDI and Terminal Services
- Designing a desktop virtualization solution with XenDesktop
- Migrating users from physical devices to virtual desktops
During the TechTalk webinar, we received many great questions but were unable to answer them in the time allotted. This blog post will attempt to provide those answers. But first, I wanted to let you know where you can get access to the recorded webinars and the PowerPoints.
Part I: Deciding between virtual desktops (VDI) and virtual applications (Terminal Services)
Part II: Designing a desktop virtualization solution with XenDesktop
Part III: Migrating users from physical devices to virtual desktops
And as always, you can follow me on Twitter @djfeller. And now to the Q/A session...
Part I: Deciding Between VDI and Terminal Services:
Q: What would be your recommended platform if streaming video or audio is needed to be delivered to a structured user environment?
A: For structured users, we typically recommend the shared, server-based desktop but you bring up an interesting design requirement. Typically when you hear people talk about some of the value-adds with XenDesktop, the focus is on the multimedia experience. Well, many of those multimedia optimizations are also present within XenApp. Now, if you have used XenApp in the past, multimedia was a little sketchy, but I encourage you to take a look again. There have been some impressive enhancements made, which you can see as part of the XenApp MythBusters series (http://community.citrix.com/display/xa/XenApp+Myth+Busters)\\
Q: We want to get away from running around the entire building updating all of our different applications constantly. So we don't want anything local. How do I do this?
A: For those users who require desktops, you would want to stream the entire desktop to the end point device or use a desktop appliance and connect to a hosted virtual desktop. This would eliminate the need to install items locally and allow you to manage everything centrally.
Q: How do we prevent users from updating their streamed desktops?
A: This is a challenge for any desktop operations environment. When users install applications onto their desktop (this could be new apps, windows updates, IE updates/plugins, etc), the support costs climb quickly because these apps have not been validated by the IT team. With XenDesktop, we have users receive their desktop from a single streamed image. If a users makes changes to the desktop, those changes will NOT remain with the desktop after a reboot. Rebooting the XenDesktop desktop results in a brand new, clean desktop environment.
Part II: Designing a Virtual Desktop Solution with XenDesktop
Q: I've been considering VDI for a while but our branch environment only has 512kb circuits. How could this possibly work in this environment?
A: The branch office situation will have an impact on the type of virtual desktop you can deliver. For example, I would not recommend using a streamed desktop for those devices unless you install a local Provisioning Services server within the branch. If that is not an option, you also have the ability to allow the branch users to utilize a hosted virtual desktop that runs within the data center. The branch office users would connect to the hosted virtual desktop over Citrix's transport protocol, which is extremely lightweight. The latest scalability numbers I saw were around 15kbps (average per user). This is only an average. If you are doing a lot of multimedia operations, then I would expect that number to increase, but if you are only doing textual operations that number would likely decrease.
Q: What is best faster processors or more memory
A: Depends on the component. # The XenServer that delivers the hosted virtual desktops needs both in equal amounts. If your virtual desktops are 2GB RAM, then on a 128GB XenServer you would only get about 50-60 virtual desktops (all because you will run out of RAM). You need to select your processors so that they are fully utilized at the same time RAM is fully utilized.
- XenDesktop Controller: CPU intensive during logons and hosted virtual desktop startup (RAM and Network underutilized)
- Provisioning Services: Network intensive. RAM is also used for file caching the vDisk images so more read requests are services by RAM instead of by disk. CPU is underutilized
Q: What's the best way to handle printing services for mobile and remote users.
A: As we are unsure what type of printers a remote/mobile user will have mapped on their local device, it is typically best to utilize the auto-creation of the user's printer and to use the universal print driver This allows the user to see their local printer within their hosted virtual desktop and to not be required to install the actual print driver.
Q: We package software with Wise Package Studio....what kind of support/compatibility will we get if we go to VDI
A: If you want to install the applications within the virtual desktops, the Wise packages are still viable options. However, if you are wanted to stream the applications into the desktop, then you need to create an application profile with the XenApp tools, as application streaming is different than application installing (which Wise does).
Q: Isn't it more efficient to allow the networking devices to compress the data stream rather than utilize CPU resources?
A: In general it is. Depending on your environment and design, there is defiantly an option to integrate a network compression solution to compress the traffic, thereby offloading these processes from the server's CPU. The Citrix Branch Repeater is able to do this for many different protocols, thereby helping to improve the overall user experience.
Q: What is the best way to handle print traffic, I am thinking of things like should this be included in base build, should you use a specialist application to throttle bandwidth usage etc.
A: XenDesktop actually contains a policy that allows you to throttle bandwidth for different types of communication, including printing. So for slower connections, you can tighten the screws on the printing traffic so this doesn't disrupt the user experience.
Part III: Migrating Users from Physical Desktops to Virtual Desktops
Q: What type of profiles do you recommend.
A: You will need some type of profile that is capable of storing the user personalization settings across many different devices. This means you will need a roaming profile solution as the basis of the environment. In XenDesktop (if using pooled desktops), a user will use a different virtual desktop everyday. Also, any changes made to the actual desktop are lost upon reboot. During logoff, we need to upload all user settings to a centralized location that all virtual desktops can access. When the user logs back into another virtual desktop, their settings are copied from the central site to the virtual desktop, thus personalizing it. Unfortunately, roaming profiles have their own issues/challenges that can be mitigated by using a profile management solution like the Citrix Profile Management.
Daniel - Lead Architect - Worldwide Consulting Solutions
Follow me on Twitter: http://www.twitter.com/djfeller
Follow me in the Blogs: http://community.citrix.com/blogs/citrite/danielf
I am posting the Q&A for the TechTalk we had on XenApp Power and Capacity Management. It was well attended (more than 50 customers and partners) with lots of time for Q&A. Check out the webinar recording if you were not able to attend.
(You can follow me on twitter)
Q) How does a combination of XenServer with virtual XenApp work? So, is it possible to first shut down the unnecessary XenApp servers and then the unnecessary physical servers running XenServer?
A: Power and Capacity Management does not manage the XenServers themselves. It only manages XenApp servers. So, if you have no virtual XenApp servers running on a XenServer it will still be powered on. Why? You may still have non-XenApp workloads running there like web servers or e-mail servers, etc. But you can use other management tools to power manage the hypervisor.
Q) Will it be possible to install the PCM agent in a "standard" provisioning server image?
A: Yes. Power and Capacity management works with Wake on LAN which is how provisioning server works to deliver images to bare metal. Wake on LAN is supported in addition to virtual machines for Power and Capacity Management.
Q) So, Can I provision my XenApp servers with provisioning server and the collector gets the different names of the server or is a special configuration needed?
A: Yes. When you install the agent, there is a configuration for Wake on LAN or Virtual machines. You select Wake on LAN and configure accordingly for the image you are creating.
Q) Must I also choose "Wake on LAN" if the provisioned XenApp server is a virtual server on XenServer?
A: You can have a single PVS image to work across physical or virtual deployments. Even when using PVS, if you are booting servers via XenServer, you would choose XenServer. If you are booting via Wake on LAN on the physical hardware then you would choose Wake on LAN
Q) Can PCM and SCOM work together?
A: Out of the box, we are not planning any integration with operations manager. However, everything being done through the GUI can be done through WMI, so this can be customized.
Q) Should the concentrator be installed on a XenApp server?
A: No. You do not want to install this on a XenApp server that hosts users sessions. You won't be able to power manage it if you do. Also, concentrators can manage servers across farms so you want a farm-independent server if you can do so.
Q) Instead of number of sessions, is there a way to set the Capacity by percentage of Server resource utilization e.g. CPU, RAM, Page File Usage?
A: Yes. We are enabling you to use nominal capacity (sessions) or load evaluator and have this all calculated as a percentage of load evaluator. This will be enabled in the final release but is not available in the technology preview.
Q) In terms of new session distribution, what takes precedence, the XenApp load evaluator or the Power and Capacity Management evaluator?
A: Power and Capacity Management takes precedence for server power on/off and consolidation only. For load distribution, the XenApp load evaluators are used.
Note that PCM adjusts the load evaluation for servers that are not selected to receive sessions. PCM will keep up to "Minimum Available Servers" available for logon. Other servers' load evaluators will be set to 20,000 (you will see that if you run QFARM /load).
Q) I am wondering how server monitoring will have to be modified to allow for servers "shutting down" and suppressing alerts. Do you have any examples of solutions?
A: EdgeSight already differentiates between planned and unplanned reboots. Since reboots initiated by PCM will be planned reboots, you should be able to create alerts only for unplanned reboots
Q) Can you please explain the process of draining a server. We publish the desktop so we have some users logged on for 8+ hours. Also we have shift workers.
A: PCM selects up to "Minimum Available Servers" to accept logons. All other servers have their LE values set to 20,000 and therefore won't be selected to host apps/desktops. When an available server reaches the optimal load, the server with highest load, but under optimal load, is chosen to receive logons.
Draining is a side-effect of the model above. As shift workers start to login, they will do so on the highest loaded servers under optimal load policy. As the previous shift logoff, their servers will automatically drain until empty. The new shift will only consume enough servers to meet its demand.
Q) If you provision server through PVS with the agent already installed and configured for a workload called "office 2003", if you want to change the workload to "office 2007" would you need to change or create a new PVS image to reflect this change?
A: Workloads can be assigned via GPO, so it's possible to use the same PVS image for more than one PCM workload. In the example above, if Office was virtualized via App-V or Streaming, then the same image could be used.
Take a moment and do a Google or Bing search on VDI vs TS. How many hits do you get? I get quite a few. Some from Brian Madden, many from Vmware, and more from other VDI providers. It's an important topic, or at least that is what some people want you to believe. I've heard about these debates, I've attended conferences where there were sessions specifically dedicated to this topic and the room was packed. I've attended these discussions and sessions before but I've left most of them thinking, "That was entertaining, but I just don't get it".
I've been doing the TS thing for more than 10 years. Over the last few years I've also been spending a lot of time focused on VDI. Throughout all of this time, I've interacted with desktop groups as well as more users than I could count. And being a TS and VDI user myself (Yes, I use both), I feel comfortable giving you my thoughts on this debate.
The debate is flawed!!!
The debate doesn't make sense!!!
If you really understand the underlying premise of both solutions you will quickly see why. It's like asking someone if they want wine or lobster for dinner. They are two different things. One is a food, the other is a drink. When you put them together, you have a very nice meal.
So what is my take besides saying the debate is flawed? Well, for that I need a little more of your time (about 1 hour). I'll be spending 1 hour talking about this exact topic during Part 1 of the XenDesktop Ask the Architect TechTalk series on August 11. If you want the full story, I recommend you attend.
This is part 1 of a 3 part Ask the Architect TechTalk Series
- Part I: VDI or TS: Selecting the Best Solution
- Part II: Designing a VDI Solution with XenDesktop
- Part III: Migrating Users from Physical to Virtual Desktops
Note: This blog was brought to you from a hosted XenDesktop virtual desktop with a XenApp-streamed Firefox browser.
Daniel - Lead Architect - Worldwide Consulting Solutions
Follow me on Twitter: http://www.twitter.com/djfeller
Follow me in the Blogs: http://community.citrix.com/blogs/citrite/danielf
Join this TechTalk and discover how Citrix ICA functions, including why single session application bandwidth testing isn't accurate. We'll dissect ICA packets and provide best practices for ICA acceleration that will make your overall network traffic more efficient than ever before.
Attend and learn:
• ICA protocol overview
• ICA bandwidth requirements and testing recommendations
• How Common Gateway Protocol (CGP) relates to ICA
• ICA performance across the WAN with and without Citrix Repeater
Click below to learn more and register for this webinar:
https://www1.gotomeeting.com/register/298972569
The following is the Q/A session from the XenApp: Fact vs. Fiction - The Truth about App Compatibility with Citrix TechTalk. For those of you who missed it or are wondering where to get materials, they can be found here:
Q: does the appcompat site differentiate between verification with xenapp hosting versus xenapp streaming?
A: Yes. In the platform column, you can see the product and whether it was hosted or streamed
Q: does per user image mean per user per app or per user for all apps
A: Per user per app. Essentially, within the user's profile, you will have a GUID on the file level the registry level. Each GUID corresponds to 1 app. As this information is stored in the user's profile, you get down to 1 user and 1 app personalization.
Q: Is streaming licensed for XenApp 4.5 EE?
A: Yes. Enterprise and Platinum edition of XenApp 4.5 and 5 gives you App Streaming
Q: What is the difference between Stream to XenApp and Application Isolation?
A: Application streaming utilizes isolation environments. In older versions of XenApp, you could install applications into an isolated environment. The Isolation Environments are now only available as part of Application Streaming.
Q: Your Twitter site.
A: http://twitter.com/djfeller
Q: Daniel...need to know what hardware you use for your home setup? how many boxes do you have?
A: My personal lab setup is very simple and not a typical implementation. I'm only looking at functionality and not scalability. Two powerful workstations (Quad core, 8GB RAM, 500MB storage). Both systems are configured with XenServer. I also have a 1TB Debian Etch system I use for XenServer shared storage. Within XenServer, I have 1 Domain Controller (SQL and File share), 2 PVS servers, 4 XA servers, 2 WI servers, 2 XD servers, 10 Vista and 10 XP workstations, 1 App Profiler
Q: It sounds like when streaming, the application runs on the client. If so, doesn't this defeat the purpose of XenApp ?
A: You can actually stream applications to the client (client-side app virtualization) or to the XenApp server (server-side app virtualization). App streaming helps overcome app compatibility issues on either location. Doing client-side allows you to use some of your workstation's power and allow you to continue using the application if the network link is broken. While XenApp streaming allows you to centralize hosting, better scalability, and better security, plus all the other benefits of XenApp.
Q: Do you recommend streaming for PACS app with high resolution graphic and clips
A: I would test to see if it will stream. Some applications just won't stream, especially if they have a Windows service or drivers. Now if the app can be streamed, then you will need to see if the app performs adequately on XenApp with the graphics. I've seen many people have PACS on XenApp with great results when they use the SpeedScreen Progressive Display technology.
Q: For offline... how much disk space for your apps. Slide 27 / 28?
A: Depends on the application. Some examples from my apps: Office is 1.1GB in size. Adobe Acrobat is 160MB, Firefox is 12MB. Remember, these are the sizes of the app profile that is copied to your local workstation for offline mobility.
Q: Would apps that require back-end connections work offline? It seems this should not without being connected to the network/internet... correct?
A: Correct. There is another TechTalk (XenApp: Take Your Data with You: App Streaming ) that talks specifically about App Streaming and offline mobility and covers this item. But long story short, apps that require backend data shouldn't be streamed for offline as they will more than likely be useless (although there are exceptions). If the app syncs when back online, then you can stream for offline (Outlook is perfect example).
Q: We're using linux and MS based Neoware thin clients almost exclusively. What problems does this present?
A: Well, you can still do server-side application streaming. Right now, the streaming plugin (offline apps plugin) is only available for the Windows platform. Many of the thin clients also use an OEM version of Windows XP or do not include enough hard drive space to store the application cache. You might want to look at XenDesktop which would give these users a desktop-like experience if that is what you are looking for.
Daniel - Lead Architect - Worldwide Consulting Solutions
Follow me on Twitter: http://www.twitter.com/djfeller
Follow me in the Blogs: http://community.citrix.com/blogs/citrite/danielf
One of my biggest gripes about Terminal Services and XenApp was that once I disconnected from the network, I could no longer use my applications. This was a major pain as I spent a lot of time on airplanes. During my 3-4 hours flights as well as 1-3 hrs sitting in the terminal, I was unable to get any work done (although I did get a lot of reading done). My problems with XenApp wasn't just limited to airports and airplanes, but also included remote connectivity. As I'm a remote employee, I spend most of my time working from my home office. There were many cases where I just wanted to spend 1 minute to look something up in a local file. But because my applications are hosted from XenApp, that 1 minute actually took 3-5 minutes (authenticate to employee portal, launch XenApp application, open file and wait for the file to be transferred from local workstation to XenApp server).
I got frustrated and installed my applications locally. This was wonderful. All of the frustrations I've had were almost gone. But this now caused new challenges. I now had to manage and maintain my applications. I had to install appropriate hotfixes/service packs. I also had to troubleshoot application issues, not something I enjoy doing. (Why does it always seem like your applications fail when you need to use them the most?) Well, believe it or not, XenApp actually allows offline access to your applications. You get to use your XenApp applications while your network is not connected, while you have absolutely no connection to the XenApp infrastructure. This sounds like a good deal. I get local usage and I don't have to worry about maintenance.
How does it work? How do you implement it? What best practices should be followed? All of these questions are the basis for an upcoming TechTalk on offline mobility with XenApp. In this TechTalk session, you'll learn about:
• How XenApp users can take their applications with them, disconnected
• How offline XenApp users are kept current
• How to eliminate app conflicts without stress
• How to follow the best practices while delivering offline applications
• How application streaming can help simplify your Vista and Windows 7 migration
Hope to see you at this TechTalk on Friday, June 5th at 1PM Eastern time.
Daniel - Lead Architect - Worldwide Consulting Solutions
You can follow Daniel at http://twitter.com/djfeller
You can read Daniel's blogs at http://community.citrix.com/blogs/citrite/danielf
XenApp admins are a creative group of people. I used to be a XenApp admin and I remember having to do tons of things to an application to get it working correctly on XenApp (but back then it was called WinFrame and MetaFrame, not even MetaFrame XP). Back in the day, applications were not built to execute on a multi-user system like XenApp. In fact, many applications today, especially those home-grown applications, are problematic on XenApp. This is where the creative XenApp admins come in. They developed numerous tweaks, configurations, hacks and custom solutions in order to get an application functioning properly. Of course this made the environment much more complex to build and maintain.
But just getting applications functioning on XenApp is just part of the problem. I remember hearing people ask about running different high-graphics or video applications on XenApp and thought, ARE YOU NUTS? ICA was built to only send those screen changes down to your video display, but with video the entire screen is changing. Talk about chaos.
THAT WAS THEN. THIS IS NOW. Things have changed for the better. Application issues are more of a myth nowadays. With new XenApp features, many of the application challenges that plagued XenApp environments are being eradicated. But unfortunately, many of you have experienced application issues years ago and haven't looked at those applications since. So I'm asking that we spend an hour going through the XenApp features focused on application compatibility in an upcoming TechTalk session.
I plan to discuss the technologies that make application compatibility easier, which will also help simplify your XenApp architectures. We will go through many of the challenges you all have experienced and talk about how these are now easily overcome. So I encourage you to attend this TechTalk session called: Fact vs. Fiction - The Truth About Application Compatibility and XenApp.
Can't wait to see you there on Wednesday, May 27, 2009 at 1PM eastern time.
Daniel - Lead Architect - Worldwide Consulting Solutions
"Learn from the past, live in the moment, and plan for the future"
Follow me in the blogs: http://community.citrix.com/blogs/citrite/danielf
Follow me in Twitter: http://www.twitter.com/djfeller
We've got a great lineup of events and podcast for you this month on the XenApp 5 Feature Pack. 3 events below.
XenApp 5 Feature Pack explained w/Doug Brown & Vinny Sosa
Date: (Available today) Wednesday, March 11, 2009
Register Here: DABCC Radio at dabcc.com
Summary: Douglas Brown interviews Vinny Sosa, Senior Technical Marketing Manager at Citrix. Vinny and Doug will discuss the recently released Citrix XenApp 5 Feature Pack. Vinny will discuss each new feature along with why this release is so important for you and your business, especially considering the current economic situation. This is a fun, engaging and transparent podcast where we'll also discuss Doug's pet peeves on Single sign-on, what the heck is that EasyCall stuff anyway, Mac and Microsoft preferences, and general techie diversions that always ensue.
Project Virtual Reality Check, a Geek Speak Virtual Webcast
Date: Thursday, March 26, 2009 1:00pm Eastern (DST) /10:00 Pacific
Register Here: wwww.citrix.com/geekspeakvirtual
Summary: With XenServer now a part of XenApp 5 Feature Pack, you'll want to join two renowned virtualization gurus - Ruben Spruijt, Solutions Architect at PQR and Jeroen van de Kamp , CTO at Log-in Consultants, as they discuss the results of Project Virtual Reality Check (VRC) - a joint research venture on optimal configuration for the different available hypervisors (hardware virtualization layers). The project arises from the growing demand for substantiated advice on how to virtualize and scale for Terminal Server and Virtual Desktop (VDI) workloads. The first phase of Project VRC compares the performance of virtualizing Windows XP and 32-bit Windows 2003 Terminal Services on ESX, XenServer, Hyper-v, and bare-metal hardware.
TechTalk on XenApp 5 Feature Pack
Date: March 31, 2009
Time: 2:00pm Eastern/11:00am Pacific
Register Here: gotomeeting.com/register
Citrix has just released XenApp 5 Feature Pack. In this TechTalk session, we'll discuss the technical aspects of the new features, with focus on the following:
- Provisioning services, Load testing services and XenServer virtualization
- Profile Management
- Workflow Studio Orchestration
- Citrix Receiver, including iPhone plugin
Q: Any recommendations for hosting or streaming components such as .NET, Oracle Drivers, MQ drivers, teradata, DB2, etc ?
A: Many core OS components will need to be installed as part of the base image. Things like anti-virus, drivers, .NET.
Q: Is there a place to find this "Leverage Existing Infrastructure" slide or the info later on?
A: Yes. In the next few days there will be 3 articles released to the knowledgebase called: Simplifying Application Delivery to the Virtual desktop (Reference Architecture, Getting Started Guide and Implementation Guide). The item you are interested in will be part of the Reference Architecture.
Q: Can you elaborate on the nature of the Citrix Receiver? One of the main benefits to XenDesktop, supposedly, is that it's clientless. It seems that the Citrix Receiver is a client...
A: Nothing is clientless. Even a web browser is a client. But in order to get to a virtual desktop, you will need a client application, the Citrix Receiver. Now the nice things about the Receiver is you aren't forced to install 20 different clients. This one client will provide you with all the features needed to receiver your virtual desktop.
Q: Could we possibly see a demonstration of a virtual desktop session?
A: You can take a look at the items on this page: http://www.citrix.com/English/ps2/products/demo.asp?contentid=163057#top
Q: If we pre-cache the app on the VDisk - aren't we coupling the app with the vDisk.
A: Not really. I consider installing an application to be coupling the app to the vDisk. Doing a pre-cache just optimizes the write cache so the app starts faster. Remember, with streaming, the application is not installed and you only see the applications you have been granted. Now if you have pre-cached an application and you now have an application update, do you update the pre-cache? Depends, of course. If the update is major, meaning it changes many files, then I would update the pre-cache because these updates will cause the write-cache to expand. However, if the update is minor, meaning it only changes a few files, just update the application profile package and forgo the pre-cache updates. When the pre-cached application starts, the updates will be streamed down to the virtual desktop. This will increase the size of the write-cache, but because the updates are so small, the write cache growth will be small.
Q: Do you maintain a list of applications and how resource intensive they are?
A: There is a Citrix site called Citrix Ready (CitrixReady.com). There are a fair amount of applications listed on that site.
Q: For those of us who have not moved into the XenApp Realm yet and are trying to determine which product meet our needs, is there a better source of information, or a 'buyers guide' that helps us determine the correct path, XennApp, XenDesktop, etc?
A: See if this document helps: http://www.citrix.com/%2Fsite%2Fresources%2Fdynamic%2Fsalesdocs%2FXenApp-XenDesktopTogether.pdf
Q: How many users can access a single vDisk from Provisioning Server with XenDesktop? An example...How many Provisioning and DDC servers will I need for 500 employees vs 1001+ Employees?
A: Take a look at this recently completed scalability document. http://support.citrix.com/article/CTX119775
Q: If I still have to manage the client why would we want to create XenDesktop? I am not seeing the return based on the large infrastructure this will require to install.
A: Excellent question. There are many scenarios where it makes sense. Below are a few, but there are many more. It all depends on your business and challenges experienced with the distributed computing model. # Forgo workstation upgrades but still utilize the latest Operating System and applications. Ever run Vista on an old workstation? You can now
- Use Desktop Appliances: They are slim devices that simply connect to a virtual desktop
- Remote users: Use your home computer without having to install apps or copy company data
- BYOC: Bring Your Own Computer allows you to use your own personal workstation while still having a secure and separate corporate computing environment.
Q: Since streaming is regarded as a primary delivery recommendation, how do you get the network team on board since they occasionally present resistance towards this distribution method
A: Yes, working with the network team is critical. How much data do you think is transferred just to boot the OS? Remember, we ONLY stream the parts needed. So even though Vista is gigs in size, we are only streaming about 180 MB of data. XP is roughly 90MB. However, for enterprise deployments, you would want the physical design of the environment to have both ends of the stream to be in close/fast proximity. The Provisioning Server should be located on the same high-speed network as the XenServers that will receive the stream for the virtual desktops. This helps control where the network usage is going to occur.
Q: You mentioned that if there are applications that need a lot of resources and they are installed on XenApp server they could hog the XenApp server. Does XenApp have an HA (high availability) architecture that would allow distribution of the XenApp load dynamically to hot standby XenApp servers?
A: XenApp does have a powerful load-balancing solution to distribute load based on any number of configurable parameters (CPU, memory, page swaps, user load, etc). However, these algorithms only come into play during the start of a new session. Once your session is on a XenApp server, that session remains on the XenApp server until the session is closed. So, you could wind up with a bunch of users on a XenApp server (which is good), until someone runs a resource intensive application that can potentially slow down the entire server because resources are shared.
Q: You recommended Stream Applications for Base, Anomalous and Resource Intensive apps. Stream from where, from XenApp?
A: Yes, application streaming comes from XenApp. The XenApp servers will manage application enumeration and launching. If you select a streamed application, you will obtain the stream from the Application Hub (like a file server) controlled by XenApp.
Q: What is a hosted application?
A: A hosted application is one that executes remotely on XenApp. All resources used are resources on the XenApp server.
Q: What happens when Provisioning Server goes down? Are existing workstations cached and still working and only new stream requests are impacted? Or are all workstations down?
A: Because there is no local disk on the provisioned desktops, if Provisioning Server fails, the desktop pauses until the stream is reestablished. This is why we recommend turning on the HA option for Provisioning Server. This will help overcome this potential risk.
Q: When pre-caching the streamed apps, would you recommend storing those in the base OS vdisk or in a separate disk attached to the VMs?
A: Pre-cache into the OS vDisk.
Q: When Streaming apps, will I run into problems when I have a suite of applications that make calls to each other. I.E. MS Office, Email and Document Management Systems?
A: Not with XenApp 5 application streaming. In previous versions, applications could not talk to applications in different streams, but that challenge was overcome in XenApp 5. So if you put Word, Excel and PowerPoint in separate application streams, they can still work together.
Q: Would this work for remote users, or is network connectivity required
A: Right now, you need a network connection. But Citrix has announced Project Independence which provides a client-side hypervisor where we can think about doing offline virtual desktops. Take a look at the video: http://community.citrix.com/display/xd/independence
Q: What is the process for preparing an application for streaming?
A: You need to run through the installation of the application with the Streaming Profiler. The profiler will take the installation and create an application package used for application streaming. Once the profile is created, you simply publish it like any other XenApp application.
Q: What is the typical time to first launch for a streamed application?
A: It depends on the application size and the network speed. When properly configured, the actual streaming of the application should be very fast, one or two seconds)
Q: What type of apps are not appropriate for this solution?
A: There are still some issues with applications that install services on the system or install OS-level items (.Net, drivers, etc) . Many of the other challenges have been overcome.
Q: Are streamed applications isolated to the extent that they are not aware of and cannot interact with another streamed application?
A: Yes and no. Yes in that what you say is correct. Streamed applications do not interact with other streamed applications. However, in XenApp 5 you can configure rules for the applications so they can talk to other streamed applications. It is a pretty cool feature that overcomes some major challenges with application streaming.
Daniel
For those of you who were not able to attend the live event or wish to re-watch it, you can get to the recording by going here: http://www.citrix.com/English/NE/events/event.asp?eventID=1685355
Q: Where can I get NeScaler training
A: You should check out the Citrix Training website for information on classes and locations. (http://www.citrixtraining.com/courses/courses/index.cfm)
Q: Is there Web Interface and XML Broker Monitors part of Citrix Access Gateway Ent.?
A: Access Gateway Enterprise Edition is a component on the NetScaler platform. In order to use Access Gateway functionality along with the load balancing functionality, you will need to have the correct license for the NetScaler platform. Please take a look at the Citrix NetScaler Editions description (http://www.citrix.com/English/ps2/products/subfeature.asp?contentID=1683492)
Q: In the demo being shown, if the application is only available via the Minneapolis datacenter, but the user is closer to the Ft Lauderdale datacenter, is it possible to configure the NS/AG to redirect the connection to the Minneapolis NS pair instead?
A: Excellent question. The challenge with your question is that NetScaler does not know which application you intend to launch when it decides the most appropriate data center. Even if the NetScaler sends you to the Ft Lauderdale data center, you will still be able to launch an application only available in the Minneapolis data center, but you still have your SSLVPN session going to Ft. Lauderdale.
Q: If you have redundant WI and/or XML Broker servers set up does NS determine that the Primary has gone down and alert the admin that redundancy is no longer there?"
A: These should be SNMP traps that you could pick up with a management tool to alert the administrator.
Q: What happen if we have two sites with different subnets and we have two DNS over NAT?
A: Two sites with different subnets, NAT, etc is fine. Your configuration will just be different and include different addresses. With multiple DNS servers, you just need to make sure that the fully qualified domain name you setup as part of Global Server Load Balancing is configured on both DNS servers to point to the NetScaler devices, which are the authoritative DNS servers for that domain name.
Daniel
I had some really great questions based on the TechTalk of "Simplifying the Migration to XenApp 5 with XenServer". Many of the questions focused on the actual aspects of using Provisioning Server. As many of you are unfamiliar with the solution, i created a video that would help you better see what this solution can do for you. Hopefully, the video will help answer your questions.
Watch this Video to see how Provisioning Server delivers XenApp
Also, if you want to replay the TechTalk, you can access it from here.
During the TechTalk, i mentioned a few white papers that were created focused specifically on this topic. Click on the item for the doc.
Q: I didn't understand how you take an existing server and turn it into a virtual server?
A: You have to reinstall the physical server with XenServer. After that, you can provision new virtual XenApp servers. The XenServer install takes 10 minutes(very easy) and streaming a new XenApp server takes about 30 seconds, which is the server boot time.
Q: After a server is provisioned with the OS, how can it be automated to install/setup Citrix and then publish apps ? Are these manual steps ?
A: The provisioned server is completely configured. It will have XenApp and the applications installed. The XenApp integration utility for Provisioning Server takes care of all of the lower-level changes to add the new provisioned servers to the XenApp farm. The only thing you have to do for a newly provisioned server is to publish the applications on the server.
Q: How can Citrix XenServer or Provisioning handle differences in hardware when deploying ?"
A: XenServer is a virtualization layer sitting between the hardware and the operating system. The provisioned, virtual XenApp servers will use the XenServer drivers. This means a single driver, the XenServer driver, can be used across a wide range of different physical hardware.
Q: Can you run XenApp 5 on Windows 2003 Server environment?
A: Yes, the same process explained within the TechTalk can also be used for XenApp 5 on Windows 2003. Actually, this process can be used for future versions of XenApp.
Q: Will the XenApp run on a VMware environment? We currently use VMWare."
A: Yes. It will run on VMWare ESX and also on Microsoft Hyper-V. However, I would recommend you take a look at performance results from INDEPENDENT tests. XenServer was optimized for XenApp workloads. As you are very aware, XenApp is very unique in that many users are physically on the XenApp servers, which causes huge spikes in context switches due to the sheer number of applications and processes running. To get the best performance, you need a server virtualization solution that understands the workload and adjusts accordingly. This is done by a single configuration option in XenServer. I'm concerned that if you simply select VMWare because you already use it for other workloads that you will be very disappointed in the results and turn away from the benefits of virtualization. I encourage you to take a look at these items:
- Simon Crosby's blog regarding VMWare's "Scalability Tests": http://community.citrix.com/blogs/citrite/simoncr/2009/02/02/VMware+Wins%21+%28Bad+Science+Required%29
- Independent Tests from Project Virtual Reality Check: http://www.virtualrealitycheck.net/
- Tolly Report on Virtualizing XenApp: http://www.tolly.com/DocDetail.aspx?DocNumber=208304
Q: Does vDisk support multiple drives? C:\ and D:\ or just the system drive?
A: Yes
Q: Explain the drag and drop of published apps...Example. Does this install the published apps?
A: Depends. If you are using streamed applications on the XenApp server, it will. If you are using installed applications it won't. However, I'd recommend that your base vDisk image from Provisioning Server contains the installed applications. That way, when you provision servers, you can go into the management console and drag the published application onto the new server. So if you have a XenApp farm with 3 different silos of XenApp servers, based on the applications they host, you will probably want to have 3 different Provisioning Server vDisks (images).
Q: How do you determine the MAC address for the Virtual server? how do you avoid existing MAC address of other hardware address.
A: Within the XenCenter console, you can see the MAC address for each virtual server without being required to go into the virtual server's console. It shows up in the networking tab.
Q: If we upgrade to XenApp5 will the version 10 of the Citrix client still work?
A: Yes, but the users will not be able to utilize new XenApp features that require a newer client.
Q: If your vdisk Image on the provisioning server is taken from the test server, how does it get a new name and IP information each time it is applied to a different VM server?
A: This is the magic of Provisioning Server. This got me when I first was introduced to Provisioning Server. It uses the target device name you create within the Provisioning Server console. The provisioned image will use that name. That name will also be in Active Directory with full membership in the domain. As for IP, that is all via DHCP. If you want your provisioned servers to have static IP addresses, you can create reservations within the DHCP based on the MAC address.
Q: Is there a way to Provision actual XenServer?
A: Not at this time.
Q: It is very disappointing that you are not addressing the client portion of conversions and that you advocate including applications in the base images. I know that you believe that clients are not impacted, but the reality is that that is not the case. Until you figure out a way to address the server hardware dependencies, the required client coordination, and the inability to layer applications automatically after the base image, I don't expect to be able to migrate to a new version without it taking months. It's also highly unrealistic to expect that we could upgrade our environment without having a dual-version environment.
A: I'm not sure I understand this question. During the migration, you will most likely have two versions running at the same time. You need to use Web Interface to enumerate applications from both farms. Recommended that you migrate entire XenApp silo's over at once. If you can't do that, then you need to have applications in one farm published to some users and the same applications in another farm published to the other users. That way you have enough resources in both farms.
As for the including applications in the base image, that is really based on the application. If you can use XenApp Application Streaming, then you don't have to include the applications in the base image. A XenApp image, with no applications could take on any role you wanted and host any application you wanted just by publishing the appropriate applications.
Q: Regarding the cloning, does XenServer take care of the post clone steps for XenApp and also does it modify the servers' SID to prevent duplicate SID's in the environment
A: Yes, as long as you setup your VM Template correctly. Cloning is a complete duplicate of the original. If your template VM that you will use for cloning is setup in a SysPrep'ed state, then all clones from it will have a new SID, name and identity. However, using Provisioning Server, you don't use the SysPrep-type utility. Provisioning Server changes the server's identity based on the name you specify in the Provisioning Server console.
Q: am I correct in thinking that XenApp has its own VM and does not 'sit' on a separate VM product (like VMWare)?
A: XenApp would sit on a separate product that is called XenServer. However, because XenServer and XenApp are owned by Citrix, great lengths have been gone into making sure you get the best performance possible, and that it is as easy as clicking a button.
Q: We're already doing this with VMWare VMs. Are there any advantages to switching to XenServer VMs? (Especially performance / ease of management improvements.) We're currently running ESX 3.5 and XenApp 4.5; we're definitely upgrading to XenApp 5.0 (in process) and considering switching to XenServer.
A: I strongly encourage you to take a look at these items. In ages past, I would not have recommended virtualizing XenApp because the performance hit was too great, basically you are throwing hardware away. However, that changed in XenServer 4.1. XenServer has a special optimization setting for XenApp workloads that greatly improves performance. Take a look at the following for more information (some are from independent, non-Citrix, sources):
- Simon Crosby's blog regarding VMWare's "Scalability Tests": http://community.citrix.com/blogs/citrite/simoncr/2009/02/02/VMware+Wins%21+%28Bad+Science+Required%29
- Independent Tests from Project Virtual Reality Check: http://www.virtualrealitycheck.net/
- Tolly Report on Virtualizing XenApp: http://www.tolly.com/DocDetail.aspx?DocNumber=208304
Q: What about the server name being the same as the image.
A: Provisioning Server will use the target device name you enter in the Provisioning Server console. Each server will then have different identities.
Q: When is Dan coming back to Cleveland to buy more Chinese food?
A: LOL, I all of the sudden have a huge craving for it.
Q: Does all the ""automation"" require Workflow Studio? If not, what value does WFS bring above what's part of provisioning server?
A: No, Workflow Studio is not required or used on any of the items I spoke about. Think of Workflow Studio as a way to automate tasks that you have to do on schedule (like server reboots) or when a trigger is hit (like if the load on a silo of XenApp servers is too high to spin up a new XenApp server). That being said, you can automate just about anything, you just need to decide if the time required to build your workflows will save you time in the long-run.
Q: Does dynamic VHD resizing negatively impact performance of the target server?"
A: Yes and No. I love answers like that. First, it will because you have to keep expanding the disk and that takes resources. But no because when the vDisk is in production, it is in a read-only mode (Private image). That means changes are not kept within the vDisk, so the vDisk will not expand.
Q: Where and how are all the parameters for the specific machine stored: machine name, domain name and SID, domain password of the domain machine, etc.
A: Provisioning Server takes care of it. The name is based on the target device name you set in Provisioning Server, which is kept in the Provisioning Server database. The domain information is also configured in the Provisioning Server Console. Provisioning Server also maintains and manages the machine's password and keeps it updated with Active Directory.
As promised in the TechTalk, here is the the link to the power point and following is the summarized attendee Q&A.
Web Interface Q&A
Q: Can Web Interface front end both XenApp and XenDesktop?
A: Yes. Use the latest Web Interface 5.0.1 that supports XenApp and XenDesktop
Q: Does the account unlock feature of Web Interface require password manager?
A: Yes
Q: Can you use Web Interface 5.x with PS 4.5?
A: Yes
Q: What are the companies you listed in your presentation that are doing Web Interface customizations
A: www.extentrix.com and www.techstur.com
Q: Web Interface changes are great, but what my users really want is PNAgent support via CSG. When is that going to happen?
A: This is supported with the latest XenApp client and Secure Gateway 3.1
XenApp clients Q&A
Q: Will there be a XenApp client for BlackBerry?
A: Since our Blackberry client partner ROVE suspended support for ICA Client, we are working with a new partner to provide similar support. Stay tuned.
Q: Can you use the new XenApp Plugin with PS 4.5?
A: Yes
XenApp Upgrade/Migration Q&A
Q: Can we upgrade from PS 4.0 to XA 5.0 or do we need to upgrade to PS 4.5 first?
A: You can move directly from PS 4.0 to XA 5.0. For specific details, refer to the upgrade/migration white paper and attend the "Upgrading/Migrating to XenApp 5 TechTalk" as well.
Misc Q&A
Q: What is Citrix Branch Repeater?
Q: Citrix Branch Repeater is an appliance that combines our WAN optimization technology with Windows Branch infrastructure services. Visit the branch repeater page for more information.
If you attended the live TechTalk, there were more questions than I could answer in the time allotted. If you want, the recording of the webinar can be found here. Also, don't forget to check out the guides and reference architecture for the end-to-end virtual desktop solution:
But now it is time for the Q&A...
Q: So I have Presentation Server 4.0 and can publish desktops. What does XenDesktop do differently?
A: An Excellent question and a great one to start this blog. One of the big differences between a XenApp (Presentation Server) desktop and a XenDesktop desktop is in XenDesktop you are essentially on your own workstation. This means you can more easily allow your users to personalize and customize the applications to best suit their needs. One of the major concerns I've seen and heard from numerous organizations using published desktops on XenApp was the desktop was static. They couldn't change their backgrounds. They couldn't customize their applications. They couldn't do certain tasks because the XenApp server was locked down so tightly because that desktop is shared by many users. In XenDesktop however, you can let your users modify the settings, customize the look and feel and try to better align the desktop with their job function. On another aspect, there might be applications that just don't work on Terminal Services or XenApp for any number of reasons. However, XenDesktop is not built a multi-user operating system like Terminal Services. Is it meant for desktop operating systems like Vista and XP. If the app works on your desktop, it should work on the virtual desktop.
Q: Can you please elaborate on the desktop receiver? How different is it from an ICA client, and will it be available for a variety of thin client devices?
A: In part, the desktop receiver is similar to the ICA client in that it allows ICA connections to XenApp and XenDesktop sessions. The Desktop Receiver also includes visualization customization options through the use of a toolbar in the virtual desktop window. If you just used the standard ICA client, a connection to XenDesktop would work, but you would be unable to fully customize the view.
Q: Will the user notice any slowness during a XenMotion transfer?
A: Yes. The user will most likely experience a pause or slowness in their session (100-200ms) during a transfer. However, the session and the data will not be lost. In most instances, the user will be completely unaware of the pause unless they are staring at the monitor and interacting with the session.
Q: Roughly how many VMs can a controller handle?
A: I wish this was an easy question to answer, unfortunately it is not. I can tell you that we have seen a single controller manage 1500 desktops without reaching a the breaking point (standard server hardware was used 2 processors, dual core, 2 GB RAM). Because XenDesktop is based on a farm architecture, we can simply add another desktop controller when one becomes maxed out. If you remember the processes that occurred during a virtual desktop startup, it essentially comes down to the virtual desktop registering itself with the controller and then the controller routing a user request to the virtual desktop. These processes happen quickly with little impact to the server. Once the virtual desktop is up and running, very little activity is required by the controller except to verify the virtual desktop is still running.
Q: To provide high-availability for the AppHub, you used a NetScaler to load balance the requests. Do you need to load balance multiple NetScalers?
A: No. There should be 2 NetScalers in the architecture though, setup in a HA Pair. The HA Pair will be in an Active-Passive mode. If the Active NetScaler were to fail, the Passive NetScaler would take over immediately.
Q: So where do you install the applications if you don't install on the virtual desktop?
A: It depends how you want to deliver the application. The recommendation is to stream using XenApp and to host using XenApp. When the user is logged onto their virtual desktop, the Application Receiver (similar to PN Agent), will auto-logon with the user's credentials. The App Receiver will show a list of applications for the user on the virtual desktop, start menu or system tray. Those applications are not installed, they are just icons. When the user selects one icon they will
1. Hosted: start a session on a remote XenApp server and execute the application from there
2. Stream: have the application streamed to the virtual desktop on-the-fly. The application will run from the virtual desktop.
Both options are valid and appropriate for different circumstances. That is a longer discussion, which I hope to extrapolate on in an upcoming blog post. Hmmm, did I just commit to something else? I gotta stop doing that.
Q: What impact would XenDesktop have on apps which are not Windows Terminal Server compliant?
A: They should work. Terminal Services is a multi-user OS and we try to run single-user apps on top of it. Most applications work fine, but there are a handful which do not for some reason or another. XenApp has tried to overcome these challenges with technologies like AIE or virtual IP, but there are still some apps that don't play nicely on a multi-user OS. With XenDesktop, you are using Vista or XP. That desktop, for the duration of the session, belongs to a single user. This should help to overcome many of the app challenges we have all experiences with a Terminal Services infrastructure.
Q: Does each XenDesktop instance take up a citrix license?
A: Yes. Each virtual desktop connection equates to a XenDesktop license.
Q: Do you have to have XenDesktop with XenApps?
A: No. You can run XenDesktop without XenApp and it runs fine. The integration of XenApp with XenDesktop allows for the reduction in the number OS images you must maintain because the applications have been removed. For example, your entire organization probably runs 1 or 2 desktop OS but you have more than 1 or 2 desktop images. Why? Probably because of the application set.
Q: Do you have to buy separate licenses for each provisioning server? Or do you get rights to configure a dev/test and production server when you buy the product.
A: Provisioning Server licensing is based on streamed desktop. So you can setup a Provisioning Server in Production and Test and they don't require a license until you stream desktops. Then each streamed desktop requires a license. If no license is available, the desktop will shut down after a few minutes.
Q: How do the vm's continue to run if the host physically goes down in the case of a hypervisor failure?
A: If the host physically fails, the virtual machines go offline as well. Any unsaved data is lost. The virtual desktop will restart on another available XenServer. The time required will be based on how long it takes for the virtual machine to boot. Think about this as well, if your physical desktop fails, power outage, etc, you also lose everything unsaved.
Q: What do you do about applications that aren't supported in XenApp, do you then have to have an image that contains that app?
A: No. If the application doesn't work on XenApp, I would suggest trying to create an application profile for the app. That profile will then stream down to the virtual desktop when the user requests the application. The app will run ontop of XP or Vista and not XenApp. This should help with those troublesome applications.
Q: Do we need to install the applications on all the desktops or only on the base OS
A: Ideally, you don't install the apps on the base OS. The base OS is just the OS and some agents. When the user logs on, they automatically get their applications from a XenApp backend. When the user selects an app, the app is either launched remotely from a XenApp server or streamed down to the virtual desktop. If you must update the app with a hotfix, you update the application profile once, and those updates are streamed down to all virtual desktops automatically.
Q: I have Presentation Server now. What are the migration steps for moving to XenDesktop?
A: If you already have your Presentation Server (XenApp) architecture, then your move to XenDesktop is fairly straight forward. You want to leverage your XenApp install to better delivery applications into the virtual desktop. I would suggest looking at the Pilot Reference Architecture and the Implementation Guide to help you through the setup and integration.
Q: I use ISA to publish my internal URLs. Is there a way in XenDesktop to use a different port for the URL that it gives out?
A: Many of the ports and addresses inside of XenDesktop are customizable.
Q: Could one use Citrix Access Gateway or Netscaler for secure desktop delivery?
A: Yes. That is the best integrated solution. With Access Gateway or NetScaler, you can setup secure, remote desktop delivery without requiring users to open up a full VPN tunnel. They will instead be able to encapsulate ICA traffic inside of SSL so it is secure over the Internet. If you go with NetScaler, you have the option of using and integrating the high-availability options for XenDesktop like load balancing and global server load balancing. These materials (Reference Architecture and Implementation Guide) explain how this works for a XenApp environment, which would be similar to a XenDesktop environment.
Q: Is the app receiver like a PNAgent?
A: Yes, that is the best way to think of it for those familiar with PN Agent.
Q: When Hypervisor #1 goes down, how does Hypervisor #2 know about the #1 server's session's virtual memory and use it to run those sessions on Hypervisor #2?
A: It doesn't. If the hypervisor fails, then the data is lost. You can only move a running VM to another XenServer without losing data. If the XenServer physically fails, then the virtual machine can be automatically restarted on another virtual machine.
Q: What is the difference between the VD Receiver and the XenApp ICA client 10.2?
A: The main difference right now is that the Desktop Receiver contains the functionality for a toolbar allowing you to more easily customize the window of the virtual desktop.
Q: You mentioned the User Profile Manager provides some cross-platform compatibility, can you expand on that?
A: I would recommend taking a look at David Wagner's blogs on the UPM here:
http://community.citrix.com/pages/viewpage.action?pageId=34439480
http://community.citrix.com/pages/viewpage.action?pageId=35291139
http://community.citrix.com/pages/viewpage.action?pageId=33587458
Q: Can machines be added to the Desktop Broker that do not have the XD Client, but instead just use a traditional RDP or VNC connection?
A: At this time, the connections are through ICA and require the Virtual Desktop Agent installed on the virtual desktop. The agent is responsible for the ICA connection as well as registering with the XenDesktop controller.
Q: You said that XenDesktop is supported on Virtualization OS other than Citrix - Microsoft Hyper-V and VMWare ESX; is it supported on the Oracle VM also?
A: Not at this time.
Q: Can this support multiple versions of the same software suite? I.E. I have most of my users using Office 2003 Pro but I have a select group using Office 2007 Pro Plus, can this be done with XenDesktop?
A: Yes. You can either have the apps available for different users (one user group gets 2003 and another gets 2007) or you can have both apps be available for all users simultaneously and be executed from the same virtual desktop when the applications are streamed with XenApp.
Q: I have several users that need to use Adobe Acrobat Professional and at this time, Acrobat will not install on a Terminal server, this causes us to have to have local PCs for these users, does XenDesktop adress this issue and allow me to give my users, who need it, access to Acrobat Pro?
A: Yes. You should first try to have a base virtual desktop image and stream Acrobat Pro down to the virtual desktop. If the app streaming does not work, you can also create a Acrobat Pro virtual desktop where the application is installed and part of the base OS. That base OS will be published to the appropriate users.
Q: Can you "publish" a virtual desktop from xenapp server?
A: Yes, but that virtual desktop is not the same as a XenDesktop virtual desktop. See the very first question.
Q: What thin client devices can this be used with? Is there a thin client with Desktop Receiver? Does this work with Sun Ray's and Sun Secure Global Desktop
A: Take a look at the Citrix Ready site. There is a specific section focused on Desktop Appliances.
Q: Does this work with non x86 UNIX/Linux OS's
A: Currently it only works for XP and Vista.
Q: Can a user change clients without losing their virtual desktop. i.e. can I disconnect form machine 1 go to machine 2 and reconnect and still have the original virtual desktop and continue with the original virtual desktop. Also, does the system keep running while disconnected (i.e. a compile would continue)
A: Changing endpoints but going back to the same virtual desktop is possible with a feature called Workspace Control (it is part of XenDesktop). As for running while disconnected, it can you if you want it to.
Q: How do you handle boot storms?
A: Get an umbrella. 
This is actually a very serious concern. If you try to boot up 1000 virtual desktops at once, you will most likely have some challenges on many fronts, just due to the impact on everything. This will in turn result in users not getting to their virtual desktop or being required to wait a very, very, very long time. XenDesktop allows you to set idle limits based on the time of day. If the morning rush starts at 9AM, you will want XenDesktop to start prepping the environment around 7 or 8AM to make sure everything is ready for the rush. You do this with the Idle limits shown in a previous picture.
Q: Is the OS image hardware independent, or do you have to have a separate OS image for each hardware variant in your environment?
A: If you are running on XenServer, then all images have the same hardware footprint (the XenServer virtual space) even though the XenServer might be on different hardware. You can use the same OS image to stream to a XenServer virtual machine and a physical server by configuring a common image where drivers are incorporated into the base image.
Q: How would this be in a WAN env?
A: Pretty good. The protocol XenDesktop uses is Citrix's ICA protocol which has been used for years with XenApp (Presentation Server, MetaFrame). This protocol only sends the screen updates down to the end point. So when you are typing in Word, only the images of the letters get sent, if they changed. ICA also has been enhanced greatly over the years to support audio, video and numerous other areas. Truthfully, the only way to be certain it will work for you is to try it out by getting the free evaluation kit.
Q: Our env is highly integrated, we have found that streaming applications to be nearly impossible.
A: By highly integrated, I assume you mean many of your applications rely on each other. App streaming is a great idea, but this was a huge problem. First, the background. When you stream, each app is in its own container. Those containers are separate and do not interact. That is a major problem for environments like yours. What ends up happening is you have 2 different enterprise applications that each rely on Excel. You create one profile for one enterprise app and include Excel. You then create another profile with the second enterprise app and Excel. When you have updates to Excel. You have to update both profiles. This is hard to manage and maintain.
Have you looked into XenApp 5, just released? It has major updates to XenApp streaming where these different containers can now talk to each other. So in the previous example, you would have 3 profiles, 1 for each of the two enterprise apps and another profile for Excel. You configure the profiles to work with other profiles. This should help you overcome the major challenges you experienced in the past.
Q: Does this require an AD schema update?
A: No. It does use AD, but it does not require Schema updates. (thank goodness).
Q: Streaming is overbilled it doesn't address application integration
A: I would love to hear more. I agree in the past App streaming was a challenge because of communication limitations between applications, but with XenApp 5, those challenges are being mitigated with inter-isolation communication.
Q: Can you use a Microsoft load balancer to replace the NetScaler?
A: Yes. There are many differences that would take a lot of time to explain, but for simplicity, NetScaler has specific smart monitors and high-availability options for XenApp and XenDesktop that makes it easy to configure and setup.
Q: Is it possible to stream this over the internet at all? For example hosting the desktop at a datacenter
A: Well, the desktop and application stream would stay within the data center. Users would connect to the virtual desktop in the data center with the Desktop Receiver, which relies on the ICA protocol.
Q: What happens if there is no controller available?
A: If all of your XenDesktop controllers fail, currently connected users will be fine. New connections will not be allowed.
Q: If the user count is small and all use same apps would it make sense to install all apps on provisioning server and by-pass streamed/hosted options.
A: It does make sense and is a possible option.
Q: Does XenDesktop with installed apps optimize video/audio significantly more than a VMware VDI desktop?
A: Hosted, installed or streamed apps really don't make much of a difference when you talk about the optimization of video and audio t the endpoint. What does play a major part is the delivery protocol. The Citrix protocol, ICA, is used by millions of users who connect to XenApp published applications. That same protocol is used to delivery virtual desktops. Truthfully, the only way you will be able to see is to try it out for yourself.
Q: How do apps that are launched from other apps work - things like GoToWebinar or Flash, which are launched from a browser? What about plugins that require installation that are not on the gold desktop?
A: Plugins and flash and other items that were not part of the base OS image can be installed on the virtual desktop by the user. However, that installation only impacts that particular virtual desktop. The changes made by the installation are contained in a write cache. When the user reboots the virtual desktop, that write cache is destroyed. The next time the user connects to the virtual desktop, they would have to re-install the agent. This is a big reason for identifying the needs of the user. It allows us to identify the agents and plugins that are needed. But just because it is not part of the base image, doesn't mean the user can't add it on-the-fly.
Q: Is there a plan to provide a "Offline XenDesktop" in the future? (similar to VMwares OnDemand VDI)
A: I have heard people talk about it, but am not in the product group so I'm not certain what the roadmap looks like.
Q: what is best practice for managing XD workstation log files, taking into account that the log data is lost after every reboot?
A: the log files would need to be stored on a network share that is persistent.
Q: Does this support any Linux Desktops?
A: Not currently
Q: Do you absolutely need the Access Gateway? I have WI with the CSG.
A: I believe you would be able to use Secure Gateway instead of Access Gateway.
Q: Will XenDesktop work with VIrtual Iron and XenApp?
A: right now XenDesktop only supports XenServer, Hyper-V and VMware ESX as the hypervisor.
Q: You had to mention NetScaler. So what are all us normal or smaller companies going to use? I hear that a NetScaler starts at $20K plus.
A: You can use software or hardware based load balancers. NetScaler just includes integrated monitors and wizards to make configuration easier. However, load balancers like Microsoft load balancing would work as well, you just want to make sure that the devices you are load balancing are being monitored intelligently (but even a Ping is better than nothing).
Q: What happens when the Hypervisor fails and there are too many VMs moved to a single host? Do some of the machines get put in stasis, are they shut down, or do all VMs suffer slowness?
A: With XenServer (Orlando) you can set priority levels for the virtual machines. The ones with highest priority will be restarted on available XenServers, others will not.
Q: What happens to data in the case of an Application Hub failure caused by a XenApp server crash?
A: This is the interesting thing with XenApp and application streaming. XenApp is needed to identify and start the stream, but once the desktop receives the stream instructions, the Xenapp server is removed from the equation. So if I'm receiving my app stream, it is coming from the App Hub and the XenApp server is doing nothing.
Q: In terms of client hardware would this work with WYSE thin clients?
A: You will want to look at the Citrix Readysite for desktop appliances. Those devices that are not on the list might work, but you want to test.
Q: What are the differences in performance installing this on ESX server 3.5?
A: I haven't seen published stats on that scenario yet. Until that time, you might want to try downloading the XenDesktop eval and trying it on both hypervisors.
Q: What's server cache??
A: The cache is for Provisioning Server (OS Streaming). Provisioning Server streams a base OS to hundreds of workstations. Those workstations use a Standard Image (Read Only) to receive their desktop OS. Any changes the user/desktop makes to that image are stored in a write cache.
Q: This question is regarding licensing. Do you utilize 2 different concurrent session licensing for any XenApp published applications running on Xendesktop? please explain how it the licensing works.
A: Licensing is such a fun topic. Citrix licensing for XenDesktop is concurrency for the virtual desktop and the app delivery. With XenDesktop Enterprise and Platinum, you get XenDesktop, Provisioning Server and XenApp for Virtual Desktops. Each one is concurrency. So when you start 1 desktop and have applications, you use 1 XenDesktop, 1 Provisioning Server and 1 XenApp license. Of course when you purchase XenDesktop Enterprise or Platinum, the licenses are part of the package. Take a look at the editions here.
Q: I guess we need to have our own SSL solution. It is not part of XenDesk components, right?
A: With Standard, Advanced, Enterprise or Platinum edition, you get Access Gateway licenses which provide secure, remote access using SSL.
Q: Is XenDesktop the same as Desktop Broker? We want to display a physical PC (a CAD workstation) across the WAN using ICA.
A: Sort of. XenDesktop replaced Desktop Broker. Desktop Broker used an ICA server as a proxy to RDP to workstations. With XenDesktop, you get ICA from your end point to the virtual desktop. Plus, XenDesktop incorporates many other technologies to make a more complete end-to-end solution.
Q: Will Secure Gateway work or does it have to be the Access Gateway?
A: Secure Gateway will work.
Q: On average how many users can one XenDesktop and XenServer host?
A: XenServer is really going to be based on the amount of RAM. Very few physical desktops utilize their CPU. If you are hosting Vista desktop on XenServer, the general recommendation for Vista is 1-2GB of RAM. If you have 64GB of RAM on XenServer, and you have 1GB RAM for each Vista desktop, you will end up with 60-62 virtual desktops (XenServer takes RAM too, which is why it isn't 64). However, the processor is the big question and the only way to really see that is to test it with real users and see how much they hit the processor.
Q: What are some of the main differences between XenDesktop and Citrix Provisioning Server?
A: XenDesktop is the complete, end-to-end solution of virtual desktops. Provisioning Server is a component of XenDesktop. Provisioning Server allows a single OS image to be streamed to hundreds or thousands of devices across the network. This has advantages of only requiring administration of a single image for many desktops.
Q: You mentioned Citrix User Profile manager is in Tech preview at the moment.... when can we expect this to be generally available? Will this be included with XenApp 5.0 which is due for release next month?
A: I don't know the release dates for User Profile Manager and it isn't part of the XenApp 5 release either.
Q: Is this only for high-speed connections (local LAN) vs WAN as some of our sites are only 256MB frame relay?
A: No. The remote delivery protocol that XenDesktop uses is Citrix ICA which has been used for numerous years by millions of users to remote connections. I've seen organizations use ICA for any number of connections including dial-up and satellite.
Q: Which of these products mentioned are extra to XenApp as we have Subscription Advantage and Enterprise Edition?
A: XenDesktop is a new product line different that the XenApp product line. XenDesktop Enterprise does include a portion of XenApp, but it only allows application delivery to virtual desktops, where the XenApp product line allows application delivery to any end point. You will probably want to check out the product matrix.
Q: I'm looking for a VPN replacement. Will you talk about the Remote user scenerio where I want to present a full desktop to a remote Work from Home user or newly aquired company where I need to provide a Desktop to them via citrix?
A: Access Gateway. This will allow you to do just what you are looking for. You have two options on the configuration: Virtual desktop only or Full VPN. The Virtual desktop only option will only allow the user to have connection to the virtual desktop over ICA. The user's endpoint won't technically be on the network, helping to protect the internal environment. With the full VPN configuration, the user will have a connection to the network. They can connect to a virtual desktop and browse the network from their end point.
Q: Is the streaming of virtual desktop accelerated over the network? We have the Citrix WAN accelerators. Does this work?
A: It might, I've never tried or it seen anyone try it. As WANScaler works at the network stream and is not concerned with files or data, the Provisioning Server stream should show a lot of duplication as it goes from the central Provisioning Server to the numerous virtual desktops.
Q: What is the best way to run CadCam Civil 3D application for remote and internal networks? Can XenApps support and deliver CadCam Civil 3D Applications remotely? How much bandwidth is required? Who can I call to assist me in setting up a Virtual desk top solution for CadCam Civil 3D
A: I unfortunately don't have experience with that particular application. You best bet would be to setup it up in a test environment and see how it functions. Citrix's Consulting group can help with this type of testing, as they have done this with numerous organizations in the past. I should know as I used to be in Citrix Consulting. The Consulting information can be found here.
Q: If I understood, we have the option to serve only the apps of the desktop to the user? Is there an installed client program on the client machine?
A: Yes, if the end point is going to get desktops, you want the desktop receiver. If the end point needs applications you use the Application Receiver. They are very similar and can be used together. In most situations, you would have the Desktop Receiver on your end point and the Application Receiver on the virtual desktop.
Q: Can this solution work on a 10/100 MB network?
A: It all can, but you have to be concerned with the number of users and the number of desktops being streamed as the streaming is using the network. Now if your environment has your users on the 10/100 network and the infrastructure components (XenDesktop, XenServer and Provisioning Server) on a faster network, then that architecture easily works as the 10/100 network will just use the bandwidth associated with ICA protocol, which is minimal.
Q: Can the desktop receiver be loaded on a thin client or desktop appliance?
A: Yes and it is, at least for the Desktop Appliances part of the Citrix Ready program.
Q: How is licensing addressed for the user, through Xen, if they need an application that requires Vista? Is there a special license needed for this use on the Xen Server?
A: Each XenDesktop component is managed by Citrix licensing. For users who require a Vista desktop and application, those licenses are managed by the Microsoft and App vendor licensing agreement.
Q: how does XenDesktop join to domain?
A: The base image is added to the domain. Then that image is provisioned out to numerous other workstations. Those workstations are also added to the domain. As the desktops are managed by Provisioning Server, the Provisioning Server will keep the Active Directory and machine passwords in sync.
BTW, I think this is the longest blog on the Citrix blog site. Thanks
Daniel
Homer Quote of Blog "I bet Einstein turned himself all sorts of colors before he invented the light bulb."
We have seen the materials, at a high-level, on how the XenDesktop solution fits together and the benefit it can provide. Are you interested in understanding more detail of the end-to-end solution?
In this 60 minute webinar, I will provide you with a very quick overview of the complete solution and then spend the majority of the time discussing the different components, what they are for, how they work and how virtual desktops are managed by the solution. We will cover the integration of the following components:
- Desktop Receiver
- Access Gateway
- XenDesktop Controller
- XenServer
- Provisioning Server
- XenApp
- Citrix User Profile Manager.
It is sure to be a great time where we will all learn a lot. And I might even explain to you on how XenDesktop relates to a Simpsons episode.
By the end of the webinar, we will all be able to understand the following song:
Desktop Receiver connected to the Access Gateway, Access Gateway connected to the Web Interface, Web Interface connected to the XML Broker, XML Broker connected to the IMA Service, IMA service connected to the Data Collector, Data Collector connected to the Pool Service, Pool Service connected to the XenServer and that's how the whole thing works 
See you there and don't forget to register here.
Daniel
Like I said in the recent TechTalk on server virtualization for XenApp, because there were so many questions, i was going to post answers to them all in a blog. And this is the blog.
First, many of you wanted the addresses for the reference materials i identified in the webinar. Here they are:
http://xenserver.citrix.vivoconcepts.com/prg/form/Citrix_runningxenapponxenserver_080225.cfm
Q: Is all this done on a Citrix appliance or is it all software based and we provide the hardware?
A: Running XenServer is all software based. You install XenServer, which takes roughly 10 minutes, on a physical server. From there you can split up the physical server into any number of virtual servers. A free version of XenServer Express and an evaluation version of XenServer Enterprise can be downloaded here: http://www.citrix.com/site/SS/downloads/results.asp?productID=683148* *\\
Q: What is the best resource for researching the possibilities of XenApp?
A: With regards to virtualization and recommendations, I would suggest the following materials, which covers different types of configuration, practices, considerations, how to do it, and much more.
- TechTalk Webinar Recording:
- Reference Architecture
- Design Considerations
- Implementation Guide
- Optimizing XenApp Performance with XenServer 4.1.0 Enterprise Edition
- Performance Evaluation of XenApp with XenServer
- Benefits of Virtualizing XenApp with XenServer* *
Q: What about network utilization with regards to Provisioning Server?
A: Network utilization is important for Provisioning Server in that the operating system image is streamed down to the virtual server. With a base Windows 2003 Server, the install size is roughly a few GB. However, Provisioning Server does NOT stream that entire image to the virtual server. Provisioning Server ONLY streams materials as needed. In fact, booting a Windows 2003 Server only streams a fraction of the multi-GB actually used in the install.
Q: Is Network Storage iSCSI or Fiber connection?
A: When you virtualize the disk with Provisioning Server, you essentially do not have any storage assigned to the virtual server. Yes, you read that right, you don't assign storage to the virtual server because the image is streamed on-the-fly. It is actually pretty wild to think about. Provisioning Server should be on an enterprise storage solution like a NAS or a SAN for high-availability and high speed of delivery to the virtual server.
I know the first time I had discussions about Provisioning Server I was like, what do you mean there is no disk. But it is true. If you stream to the physical server, you can completely unplug the hard drives. In the virtual server world, you just don't assign disks to the server. With this type of solution, you end up not having to worry about GBs and GBs of storage required for a virtualized XenApp solution. In fact, I've seen customers use Provisioning Server to help them migrate to newer versions of XenApp. Right now, let's say you are running XenApp 4.5 installed on physical servers. When the next release of XenApp arrives, you create your image with Provisioning Server and stream the image to the servers (physical or virtual). If you run into challenges with the new version of XenApp, your fallback procedure is to use the hard drives again, which still contains the XenApp 4.5 installation. Pretty cool if you ask me.
Q: Would XenServer bundle with P2V tool for free? Or we have to buy PlateSpin P2V tool?
A: The P2V tool, when it is released, will be free. You won't need to buy any third-party tools to do P2V conversions.
Q: We have VMware ESX Enterprise already. Should we get XenServer for our XenApp farm? What are the advantages?
A: I'm not a Sales person so I don't recommend products just because it is what we sell. So when talking about virtualizing XenApp, first understand that XenApp is a unique beast. It doesn't behave like other systems within the data center. It must support hundreds of users simultaneously. This requires lots of memory, lots of context switching, lots of disk access. It is different than let's say Exchange or SQL Server. Before XenServer 4.1, I would have been hard pressed to recommend XenServer as a viable solution for XenApp. In fact, most virtualization solutions would not have dealt with XenApp effeciently. But look what happens when XenSource became part of Citrix. Our engineers (XenApp and XenServer) worked together to re-architect the hypervisor to perform remarkably better for XenApp virtual machines as compared to the 4.0 version of XenServe. That being said, XenServer is optimized for the XenApp workload. Instead of making you perform some low-level funky "tweaks" the hypervisor, we just have you select the type of workload the virtual server is doing. In this case, you select XenApp. This option changes how XenServer deals with memory to align better with XenApp requirements.
Now, when you look at XenServer Platinum the picture becomes even better with Provisioning Server. Without Provisioning Server you must still manage each virtual server as if it was a physical server. This is regardless if you are using XenServer, Hyper-V or even VMware. Provisioning Server lets you focus on the role and not the server. There are fewer roles in the data center than there are servers. Easier to manage and maintain, a huge savings if you ask me. And you did But I did only touch on a two areas. Take a look at the documents (especially the reference architecture) I put at the beginning of this blog for additional information.
Q: what were your server specs for your example?
A: The scalability testing completed with XenServer and XenApp were done on a Dell PowerEdge 1950 (1 Quad-core 1.6GHz, 8GB-16GB RAM).
Q: What about users that are logged into an app, and the server is rebooted
A: A physical server, virtual server or a server receiving the image from Provisioning Server, those users are disconnected and their sessions are gone. Now if the physical XenServer fails, the virtual XenApp servers can be moved to another XenServer, a feature we call XenMotion. In this circumstance, a user might see a slight pause in their session, all depends on the current situation. But the point is in this situation, the users session and data is intact.
Q: You mentioned doing P2V of Citrix servers throughout your presentation. Are there any items to be aware of when doing this? Any resources to help with this process?
A: Well, the first is an upcoming P2V tool that will let you convert a physical server to a virtual server for XenServer. If you only use XenServer and not Provisioning Server, the only other item is to set the optimization setting for the virtual server to Optimized for XenApp. This was discussed earlier in this blog. If you are also going to stream the system with Provisioning Server, you will want to build the "golden image" how you want it to be for each server. You then must run the integration utility, which will take care of all the other configuration items. If you want instructions on how to do the Provisioning Server aspect, take a look at the Implementation Guide identified at the beginning of this blog.
Q: Did you use Provisioning Server w/ the test load, or just straight XenApp on XenServer?
A: The scalability testing was just XenApp on XenServer. I can bet your next question will be what impact on scalability with Provisioning Server have. And might I say it is a great question if I do say so myself. Unfortunately, I'm not aware of any scalability testing that shows the impact to single server scalability with Provisioning Server.
Q: How is XenApp rated on VMware ESX vs. on Provisioning Server on XenServer?
A: Unfortunately, due to VMware's end user license agreement, we are not able to publish scalability numbers for VMware ESX. No one can except VMware. We did tests against a number of virtualization vendors and found that XenServer allowed roughly 70% more users than others when running 64Bit XenApp.
Q: How large would a server image be with Provisioning Server?
A: The size of the Provisioning Server virtual disk, which I call a role, can be pretty much any size. However, you don't want to go wild with the image size. If you create a 10GB image and a 100GB image, the 100GB image will take a lot longer to build and optimize, plus it will waste space and we are all trying to conserver power, space, cooling, etc.
Q: What is the best client to use - PN, PNA or WI?
A: You tell me It really depends on what you need. Most administrators prefer PN as it allows them to make connections as they need to support the environment. Users prefer PNA or WI. PNA is great in that you don't have to go to a web page to get to your applications, so it is faster from a user perspective, but WI allows you to integrate the published resources in other pages like SharePoint. I personally use Web Interface and my favorite color is green.
Q: How can one discern how much RAM/CPU is being used on a daily basis? Does Access Suite Console give that info? (Am on PS 4.0 and use VMWare)
A: Within the XenApp Access Management Console, you can generate reports for your XenApp servers to give you all kinds of information about the overall utilization of the servers. The reports are in the Report Center. Also, you can use Resource Manager or EdgeSight to get even more detailed information.
Q: Is there a release date for the P2V tool?
A: All I can tell you is the beta is expected soon. I would log onto MyCitrix and see if you can see it in the download section. Also, Roger Klorese has been blogging about the next version of XenServer (Project Orlando). I recommend taking a look at his blogs.
Q: Is there a guideline for application roles that are not suited for XenServer virtualization?
A: Hmmm, I'm trying to see if I can think of an application that is not suited for XenServer, but I'm having trouble. Before XenServer 4.1, I would have probably said XenApp due to the overhead, but now that the overhead has been drastically reduced, I can't say that anymore.
Q: What file system do you recommend for the storage partitions on a NAS or SAN? (I think VMware has a proprietary clustered file system, Novell uses OCFSv2).
A: This is what I love about XenServer and Citrix. You can use anything you want. NAS, SAN, NFS, iSCSI. If you already use something like NetApp, use it. If you use a SAN solution, use it for XenServer.
Q: Nice to see how memory issues can be addressed with virtualization. What about CPU, network, and disk I/O being the bottleneck?
A: Excellent question.
- CPU: Not sure what issues are around CPU in the XenApp world except for CPU underutilization because of memory bottlenecks and memory limits. Virtualizing lets you completely use what you paid for.
- Network: The networking aspect is interesting. Because the physical server is now hosting multiple virtual servers, you want to make sure you have adequate bandwidth going into and out of the physical server. The network component is critical to XenApp, but the data transferred is fairly minimal due to the use of ICA. Now on the backend, the XenApp applications require data from their source. And if Provisioning Server is being used to stream the operating system, more network bandwidth is required. But these should still be within the limits of the current standard server hardware of 1GB NICs. However, I would still recommend mulitple NICs to a single XenServer. You don't want a Homer Simpson tripping over a network cable and dropping all users from a XenServer.
- Disk I/O: In a enterprise design, I would recommend you use some type of fast storage like a NAS (regardless if you use Provisioning Server or just plain XenServer). These devices are specialized hardware optimized for file sharing. I have had customers tell me that their XenApp environments actually run faster because of XenServer and the integrated NAS/SAN.
Q: is the benefit presented on this slide in the fact that Disaster recovery is improved by virtualizing?
A: Disaster recovery is improved. With XenServer you can move a running virtual server to another XenServer. Provisioning Server also helps in the DR scenario as you can quickly re-provision systems to take on a new workload with a simple reboot.
Q: You don't have to have 32-bit apps to run on 64-bit OS. That's where you get your scalability on XenApp
A: True, you can continue to run your 32bit apps on a 32bit OS like Windows 2003. The problem is that you have a memory limit with 32bit OS. In more cases than not, you will max your RAM before you get close to maximizing your CPU.
Q: We have XenApp 4.5 running on a dev/test environment in VMware. Session connection times seem to be slow for an app to open up. What kind of things should I be looking at to find the source of the problem outside of adding hardware to the VM. thanks!
A: Well, first I would say try using XenServer (I know, I had to say it) But seriously, take a look at the storage situation with your VMware implementation. What performance numbers are you getting from the I/O system in your setup? With XenServer, we recommend you use either a NAS or SAN type solution which provides the fastest possible disk performance. The faster your disks run, the faster apps load because they are coming from disk.
Q: What technology are you using to determine user count?
A: We are just performing scalability tests with tools like EdgeSight for Load Testing and then to get the metrics, we utilize perfmon counters and log files to analyze the results and make comparisons.
Q: I'm a bit new to XenApp but your numbers for concurrent users seemed very high. If your Visio app is using 1Gb of RAM just for you, doesn't' that mean that a max of 15 people could use Visio on a XenApp server?
A: In that example, yes. However, it all depends on the apps. For example, the scalability numbers I presented for roughly 300 concurrent users on a physical server were working with Excel only. This was used to determine overhead. Your concurrency numbers will vary based on workloads. The scalability numbers are meant to give you an idea of the XenServer overhead.
Q: Another point is disk utilization... we are often disk bound
A: Yes, disks can be a problem. Sure you can implement array controllers, use 15K RPM drives, but you are still relying on the local system to manage the file system. When you integrate with a SAN or a NAS type solution, those devices are optimized for file hosting. Optimization=Speed
Q: I have already heard that you can not clone XenApp servers... where can I learn more about this?
A: Read the Reference Architecture document identified at the beginning of this rather long blog. It talks about the Provisioning Server Integration Utility for XenApp.
Q: How do you get 200 users in 4GB of RAM?
A: By running Excel only. This workload is used to show the overhead impact between 64bit physical, virtual and 32bit. You workloads and your concurrency numbers will be different. This is to give you an idea of the expected overhead. I've actually seen other people get their XenApp servers into the upper 100s by using bigger applications than Excel. It all depends on the apps and users. That is the main problem with scalability tests, they only reflect a single type of workload and do not represent your environment. They are only meant to give you an idea of what the overhead is and comparisions against other products.
Q: Any tool like ESX Ranger becoming available?
A: ESX Ranger has many different features. I know you would be able to use something like Workflow Studio to help manage the environment from user-based, event-based or schedule-based triggers. As this product is still in beta, it is hard to tell what functionality and integrated components will be available at release.
Q: Isn't XenServer only supported on 64-bit platforms? How then would we virtualize a 32-bit Server with your scenarios?
A: XenServer is a 64bit hypervisor, but it can virtualize 32 and 64bit systems.
Q: Did you reference a 32bit version of XenServer?
A: XenServer only exists as 64bit. There is no 32bit code in the XenServer.
Q: What about PAE on 32-bit systems? This allows more than 4gb of ram to be addressed.
A: I wondered if someone was going to ask about that. Congratulations. You can use more than 4GB of RAM on a 32bit system, but there are a lot of things you must be aware of. Instead of making this blog even longer, I created another entry that discuss the PAE setting, which can be found here:
Q: Why would you keep a backup data store if you can just motion it instead?
A: In the event the live data store is corrupted and is unrecoverable. If it is, I hope you have a backup.
Q: What are your thoughts on virtualizing Provisioning Server?
A: The great answer, it depends. Virtualizing Provisioning Server will induce latency into the stream as it must go through a virtual network and then onto the physical network to the device. However, being able to hot-move the Provisioning Server to another server and easily add capacity makes virtualizing a very sound solution. I haven't seen any numbers yet as to what virtualizing Provisioning Server would do to the scalability.
Q: Running published desktops. Can I virtualize these?
A: Published desktops on XenApp, yes you can. If you are talking about XenDesktop, desktop virtualization, VDI, whatever else they call it these days, you can as well. In fact, Citrix XenDesktop is also based on the XenServer hypervisor.
Thanks
Daniel
Homer Simpson Quote of the Blog "If you really want something in this life, you have to work for it. Now quiet, they're about to annouce the lottery numbers!"
In case you haven't heard or seen , I'll be hosting a live TechTalk on Wednesday, July 23rd at 1PM Eastern covering the virtualization of XenApp on XenServer. For those of you who have read my blog, I know there are 5 of you, will know that I've been working on this aspect of server virtualization for some time. I plan on covering what you should virtualize, how you should do it and how to make dev/test environment better with this solution. So if you want to hear me talk on a great topic, don't forget to register here.
July 23, 2008
1:00 PM Easter
1 hour duration
Daniel
Shipoopi!!
(Homer Simpson Quote of the Blog: "Kids, you tried your best and you failed miserably. The lesson is, never try.")
Join Citrix Experts for this TechTalk webinar and learn how Citrix NetScaler Application Firewall prevents web applications attacks automatically-without degrading throughput or application response times!
In this session learn:
- How NetScaler Application Firewall works
- How to manage web traffic & provide protection at application layer 7
- The inside scoop on SQL injection, cross-site scripting exploits, forceful browsing & many other attacks
When
Wednesday, June 11th 2008
1:00p (EDT)
Duration: 60 Minutes
Click here to register!
Virtualizing your servers with Citrix XenServer™ is the foundation of a virtual infrastructure. Citrix XenServer™ is the simplest, most effective way to virtualize and provision your servers - making the datacenter more dynamic. When you build on that foundation with NetApp, you'll fully realize the promise of a virtualized environment. Maximize your efficiencies with the first and only one click storage adapter. With Citrix and NetApp, learn how you can:
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June 18, 2008
10:00am PST / 1:00pm EST / 6:00pm GMT
1 hour duration
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