I got an interesting item in my inbox from a friend who was speaking with VMware about their VDI solution.  He asked me if the information VMware was telling him was true. He was especially curious because he knew I wrote the Citrix XenDesktop Enterprise Design reference architecture that VMware was referencing to talk about how much better View was. VMWare's approach is laughable.  They are taking a detailed consulting design document  and trying to compare it to the VMware View reference architecture, which if you read it like I have (wasted 2 hours of my life), you will quickly see it is high-level and full of marketing spin and provides no insight.  I, on the other hand, was trying to provide all of you in the community with insight into how to design a large, and complex customer environment with XenDesktop.  Anyways, I told him the angle they were using and he thought it was ridiculous.  I was going to leave it at that, but I've been seeing and hearing more about it from others so I thought I would provide all of you with the same information.  Let's break it down: 

Scalability:

• Misconception: VMWare says that XenDesktop has poor hypervisor scalability. They say that on a 16 core server XenDesktop can only support 40 users (3 users per core). 
• Truth: The XenDesktop reference architecture for the hosted virtual desktops is 8 cores, not 16.  In the design phase, we estimated 40-50 VMs per server, which averages to 5-7 virtual desktops per core.  We were a little conservative as we were not sure how the unique applications would impact the system.  But you can look at Project Virtual Reality Check scalability white paper to get a good comparison of XenServer and ESX.  Although the design VMWare references was for XenServer, the same estimates would have been used if the hypervisor was running ESX.

Storage:

• Misconception: VMware likes to say that XenDesktop is a storage pig in that we need a lot of storage associated with each virtual desktop. 
• Truth: This particular design had a requirement to keep a few system items persistent across workstation reboots so we recommended the creation of a local, persistent disk of between 3-5GB to store items like event logs, performance metrics, antivirus definitions, etc.  This is not NAS/SAN storage; it is the storage on the physical XenServer.  Think about it. You buy an 8 core server, install XenServer, which is small, and the rest of the local storage is wasted.  We utilize that for the persistent store of the virtual desktops.  This means we cannot do XenMotion on the virtual desktops, but most customers I've spoken to do not have this requirement.  After looking at VMware's reference architecture I don't see any level of detail as to the amount of storage they require.  I wonder why not. 

Workloads:

• Misconception: VMware states that they can get more users on a hypervisor than we can.
• Truth: This is all around scalability tests, which I'm not a fan of.  I can easily find you 5 tests that show XenServer is better and another 5 that shows ESX is.  The VMware reference architecture had users connected for 14 straight hours, seems like a long workday to me. I have a question for VMWare: What company did you create this architecture for where users would work for 14 hours? Please tell me as I do not want to work there.  As we all know, the most typical system hit is during startup and logon. So by expanding the session time from a few hours to 14, the overall average utilization rates can be significantly lowered, thus providing an inaccurate estimate to the hardware
• Truth: The Citrix Reference Architecture made estimates based on the applications and expected real user workload, not simple apps and 14 hour workdays.  VMware's reference architecture was based on standard scalability samples shown below. If this was an actual user workload, I totally want to work for that company because that job looks so easy:
  • Microsoft Word - Open/minimize/close, write random words/numbers, save modifications.
  • Microsoft Excel - Open/minimize/close, write random numbers, insert/delete columns/rows, copy/paste formulas
  • Etc

RAM:

• Misconception: The amount of RAM that VMware recommends in their reference architecture is nuts.  They say they can get 96 users on a server with 96GB RAM.
• Truth: If you subtract the hypervisor overhead you are looking at "USABLE" RAM of about 800MB per virtual desktop.  I say usable because ESX has probably enabled memory ballooning.  It is true that XenServer does not have memory ballooning, but I would recommend customers disable this feature for virtual desktops.  On XenDesktop projects that use the ESX hypervisor, I also recommend disabling this feature.  Users and desktops are more dynamic than server workloads, meaning the RAM consumption is going to fluctuate greatly.  If RAM starts to decrease to the critical threshold, what happens to the hypervisor?  It must free up memory by paging this to disk.  Isn't this an intensive system process that consumes more resources at a time when resources are scarce?

End Points:

• Misconception: Vmware talks about the end points and only focus on thin clients and end points that we can repurpose with a Linux OS or locked down Windows OS. What about the newer end points that organizations have already spent money on? 

• Truth: With VMware View you still will connect to the VDI desktop and idle your local hardware. Seems like a lot of wasted desktop resources to me.  XenDesktop, on the other hand, allows you to re-use those desktops as a local streamed virtual desktop. Don't be fooled, there is more to desktop virtualization than VDI.

Provision:

• Truth: Closer to the end, the reference architecture talks about the time to provision X number of linked clone desktops.  I'm not sure if this is automated or if an admin has to do each desktop one-by-one. I'll give VMware the benefit of doubt here and say it is automated, but taking 161 minutes (2 1/2 hours) to provision 500 virtual desktops seems long to me.  I personally don't think this metric is important, even though XenDesktop is measured in seconds.  If it is automated, you do all of this in the build out phase and not in production. So the time it takes is irrelevant to me. Why did they choose to include it? No idea

So my advice to anyone who is still reading this blog... Take everything you get with a level of skepticism.  Do your own due diligence and look at the details to see if things were glossed over or if an in-depth analysis and design was completed.  That recommendation even includes the materials I post.  I try to be open and honest in my blogs, white papers, TechTalks and videos, but I am a little biased to Citrix because they pay my bills. 
If you want to discuss more, or have further questions, then Ask the Architect

Daniel - Lead Architect - Worldwide Consulting Solutions

• Twitter: @djfeller
• For the latest desktop virtualization information visit the Ask the Architect - Next-Generation Desktop site
• Questions - Then Ask The Architect

I had the pleasure of attending Gartner's Symposium and IT Expo in Orlando in October. Other than talking to a lot of customers and partners, I took time off between booth hours to attend sessions and I was especially interested in anything labeled "Cloud".
Gartner defines Cloud computing as a style of computing, where elastically scalable IT services are delivered to customers using Internet technologies. This is one definition, and there are nuances between private cloud services (which corporate IT can build inside of companies to be more responsive to business needs) and public cloud services, which will enable companies to rid themselves of IT and consume services from providers - just like manufacturers stopped having their own on-premise power generators and are now consuming power from a utility. As a member of the Citrix Consulting organization, I was curious to see what the thoughts on a transition to the cloud would be. There is a lot of press and talk about the cloud itself at this time and it is not surprising that Gartner sees Cloud Computing on top of the Hype Curve with at least 2 yrs to wider spread adoption. Before that can happen though, we will have to move through the trough of disillusionment, but after we get over the mild hangover, we can talk shop.
Gartner looks primarily at three different types of cloud providers:

• Infrastructure. Think providers of server on storage capacity a la Amazon EC2 and S3.
• Middleware: Think providers of application developer platforms like Google Apps and force.com.
• Applications: Think providers of applications that often run on the Middleware layer, such as salesforce.com, web-based email etc.

The piece that I was missing in the Gartner discussion was the Desktop in the Cloud, or Desktops as a Service (DaaS). Given that the public cloud mantra is still a bit in the future, this is not surprising, but the thought raises some interesting questions.
Unlike moving a few apps playfully to a cloud provider in non-production environment, moving a desktop into a public cloud requires a bit more thought. For one thing, the desktop must deliver the business applications and those apps often times need to talk to databases and file shares to be useful. Companies may actually keep this portion on-premise for the time being, so long as the communication from the cloud back to the datacenter performs reasonably well and can be secured properly. Consulting hint: Test the end to end response time to assess if this is feasible for your specific scenario. Given multiple regulatory questions such as "Who owns the data in the cloud? Who ensures compliance?" I would expect a lot of the backend data to remain in the corporate datacenter initially, even as desktops move to the cloud. Over time, networks will continue to provide ever increasing capacity and reliability, so the application latency introduced by backend resources is probably not necessarily going to be a showstopper.
So, let me go out on a limb and predict the future for Desktop in the Cloud (hosted virtual desktops running on shared infrastructure, accessed by end-user over public networks, used as the primary means to do work):

• Desktop in the Cloud will first be adopted by small businesses or for desktops with a limited number of apps. Host a desktop with a web browser, office productivity software connected to a cloud-hosted web server (or entirely web-based email) and maybe include software such as Quickbooks and you have a repeatable, low cost desktop that can be used from the office or from home for a low monthly charge. Employees use their own personal PC or laptop to access this environment and gone are the days where everyone directs their PC troubles to the guy or gal in the office who happens play video games in the evenings.
• Gartner stated in one session that ISVs will have to become good service providers to prepare for cloud computing. I actually disagree with that statement - it reminds me of the days when software vendors aspired to be ASP's. ISV's will have to provide software and licensing that is conducive to a cloud model. The software licensing will have to change to allow for hosting in the cloud and a subscription-based pricing model. Software and data ownership will need to be figured out and the cloud provider with the most straight forward legal terms will have a leg up.
• Desktops delivering a few critical apps will be next. Think call centers or the healthcare vertical. Those are fairly simple desktop implementations without a lot of application complexity or a requirement to let traveling users connect or work offline.
• Enterprise Desktops (those delivering pretty much any app and connect to a myriad of complex application back-ends) will be the most challenging and probably take the longest to achieve widespread adoption in a cloud model. One can imagine the offline use case being solved by streaming an offline operating system to an endpoint, and some of the emerging file synchronization solutions in the cloud ensuring that all corporate data is properly synchronized between online and offline usage.

One of the items that the industry hasn't figured out yet is a service level agreement (SLA) standard for virtual desktops. We have SLA's for servers and applications, but not for desktops, whose users are a lot less forgiving for latency for basic desktop interactions or the inability to access them. To establish and enforce SLAs for the desktop, end-to-end monitoring solutions are key that allow both the provider and the customer to pull reports on response times and overall system performance.

I remember one additional line from the Gartner Symposium keynote. According to their surveys, some 60% of CEOs believe that IT is constraining their business. What that tells me is that business leaders will need to have more trust in their cloud provider than they have in their own IT. Therefore, I predict that the Desktop as a Service providers of tomorrow will be the large system integrators. They are already trusted by many corporations to run IT end to end and have the expertise and backend capability to deliver hosted services with strong SLAs and security.

Florian Becker
Director, Worldwide Consulting Solutions
Follow me on twitter: @florianbecker

My role allows me to speak with many different people (customers, technologists, coworkers, administrators, etc). I've been able to see presentations comparing the different desktop virtualization solutions out there.  One of the problems I see is that many of the solutions only focus on one aspect of desktop virtualization, and that is the VDI model. 

VDI is only one aspect of the entire desktop virtualization solution.  This is a concept that many fail to comprehend. For example, I attended Gartner ITExpo last week and was amazed at how many people I talked to only thought about the VDI scenario (you know VDI, allowing you to have a remote virtual desktop running on a hypervisor in the data center).  When I talked to people about the other options, I could see their eyes light up.  

If you are reading this and only know about the VDI version, the I suggest you take a look at FlexCast to get a better understanding at all of the different options out there (FYI, even the CIO magazine identifies there is more to desktop virtualization than VDI). But in a nutshell, here's the deal... desktop virtualization includes:

1. Hosted shared desktop
2. Hosted VM-based VDI desktop
3. Hosted blade PCs
4. Streamed local desktop
5. Virtual Apps to installed desktops
6. Local VM-based desktop

I want to focus on the Streamed local desktops scenario. This is the one that really got people's attention at Gartner.  Why?  Because most organizations do not do a big bang effect of replacing their end point devices. Instead, most have a rolling lifecycle where each year a portion of the endpoints are upgraded and over the course of 3-4 years the entire desktop environment has been upgraded. Once the process completes, it starts over, never ending.  
 
Let's now say you are embarking on a desktop virtualization project.  It seems like  a waste of resources and money to idle those desktops that are only 1 year old. They are powerful enough to run Windows 7 and the latest applications, so why would we not use the hardware we already have?  This is where the streamed local desktop comes in. It uses the same XenDesktop infrastructure, the same OS images, the same application layer and the same personalization layer.  The only thing that changed is the hardware layer.  
 
As money always seems to speak louder than words, think about it this way: If you have 3,000 desktops and they are replaced every 3 years on a rolling cycle, that means 1,000 of those desktop are less than 1 year old.  If you estimate 50-100 virtual desktops on a hypervisor (XenServer, ESX or Hyper-V) then you need 10-20 fewer physical servers, which is a substantial cost savings (and even greater if you are using a hypervisor that costs money).

So I encourage all of you to not think about the VDI-only solution but instead to look at your environment as a whole. Chances are you will see that VDI-only might work for you, but probably isn't the best way to run your business. Think about it this way... You can create documents in Notepad, but would you really base your business on a solution that only does one thing, or would you use a more complete solution like Microsoft Word that gives you options?  

Daniel - Lead Architect - Worldwide Consulting Solutions

• Twitter: @djfeller
• For the latest desktop virtualization information visit the Ask the Architect - Next-Generation site
• Questions - Then Ask The Architect

I have recently returned from Gartner ITExpo in Orlando.  It was quite interesting, especially some of the thoughts they had around the economy and impending recovery.  One thing stated during the conference should not be a surprise to anyone, during a recession you save your money by not taking on any new projects. By not implementing beneficial upgrades to your systems. By not delivering newer versions of your applications to users.  

This does have the benefit of saving money, but this can only go on for so long.  Eventually, your competitors will stop saving and start expanding. Where will you be?  

We are at a very unique inflection point that can have lasting ramifications to your IT infrastructure.  We are:

1. Coming out of a recession. We are very likely to see a slew of projects going across the tables to install this or upgrade that. So it is looking like the next 1-2 years will have IT taking on a lot of tactical projects.
2. Getting ready for a major operating system upgrade with Windows 7. Whether you are ready or not, Windows XP doesn't have much time left, and most people are skipping Windows Vista. How are you going to migrate?
3. Able to do things that were unheard of in previous years. We can virtualize a massive server into small chunks, we can do the same to an operating system, applications, and the user's personalization layer and deliver it to any type of device imaginable (phones, PCs, MACs).  

So what does this mean? It means you can continue running your environment like you have for the last 10-20-30 years, or you can ask yourself one simple questions: "Is there a better way?"

We have a very profound opportunity to correct the issues of the past.  And if we do it correctly, the resources required to update, maintain and support our environment will greatly reduce.  So when the next recession comes around, your organization will be ready with a fast and streamlined approach towards maintaining your IT environment as well as continuously providing new services.  But where to begin?  

Take a look at your infrastructure. What area requires a lot of time and resources to maintain?  Probably your desktop environment.  Let's investigate and fix it, but let's do it right.  Make sure you look at all aspects

1. The users: what do they need and how do they work
2. The devices: what type of devices, what capabilities
3. The locations: where are they located, what bandwidth pipes are available
4. The applications: how many are there, what level of dependencies do they have, who uses what

This information is critical.  This is what you need if you want to do the desktop virtualization solution correctly, from day 1.  Is it going to be something you can do in 10 minutes? No. Is it something you can implement in 1 hour? No. Why?  Because we are taking something that is seriously complex and trying to create a solution that can scale and simplify our lives. So during the next recession, we won't have to stop delivering new services, but can forge ahead and beat your competition with an entirely new delivery solution.  
Daniel - Lead Architect - Worldwide Consulting Solutions

• Twitter: @djfeller
• Ask the Architect - Next-Generation site
• Questions - Then Ask The Architect

We have had a great discussion going about user-installed applications and the need/risks associated with this type of solution. One of the comments I received in favor of allowing users to install applications was around Firefox. For those of you who don't use Firefox, there are thousands of add-ons a user can install to customize their browser experience. I personally have about five different add-ons configured with my Firefox implementation.

Now I've been advocating the need for IT to have a process in place that can handle the expansion of the application pool for the users as needed by:

1. Taking user requests for new applications/tools
2. Validating the need
3. Delivering in a timely manner

This is all well and good until we get to the topic of these add-ons. I don't expect any IT organization to have a requirement to support the add-ons. There are thousands of them. Think about it, do you really expect your IT to be spending time messing with these add-ons? And what would it look like for the user? A Firefox application with thousands of add-ons? CRAZY (I do wonder at what point that app would crash. Maybe need a MythBuster episode on it)

All of the sudden, I had a very enlightening experience. I just got my new XenDesktop 4 environment built. I went in an started to personalize my environment, including my 5 Firefox add-ons (remember I'm using pooled desktops from a single base image with roaming profiles). The next day, when I logged onto my virtual desktop, my Firefox starts up and BAM all of my add-ons are still there?!?!

I did some investigation into this. Well, this is an example of an intelligent application design. The add-ons are located within the user's profile (the roaming portion). User's are able to customize the Firefox application without any special tools/utilities. The discussion about Firefox and the add-ons is now a non-issue as the application manages this for us.

So, 1 application down, only 999,999 to go   The point is you need to test before deciding if something will or will not work.

Daniel - Lead Architect - Worldwide Consulting Solutions

• Twitter: @djfeller
• Ask the Architect - Next-Generation site
• Questions - Then Ask The Architect

Did Brian Maddenmake a valid point about VDI and desktop virtualization that most people missed?  

Brian discussed a VDI€‰challenge, user-installed applications, which was in response to a desktop virtualization postI recently wrote about the same topic. Brian's premise was that each user needs to be able to install their own applications and should be allocated 2 virtual desktops:

1. First one locked down by IT
2. Second one is open where users would have full control

When I first read this I thought, well yes that would work but talk about a nightmare situation.  Many of the comments posted were extremely funny and I encourage you to read them (especially the one that said "Steve Ballmer must be smiling"). But seriously, if you think about what Brian is saying, it does have validity, if done correctly.

Sure there are tools/solutions that can allow users to install their own applications but we should not open the flood-gates and allow users to install whatever they desire. Not only are you looking at a management nightmare, but you are also looking at security risks, legal risks, and productivity risks.  What I can see happening is an environment that is suited to what the user needs. Something like the following...

1. Each user gets their IT-delivered desktop that includes all known corporate applications.  These applications are delivered into the desktop either through installation, streaming or hosting.  Users will inevitably try to install apps/plugins/tools into the corporate-delivered desktop.  The app will work until the user reboots (assuming shared image mode).  Once rebooted, the app is gone and the cycle starts again.  If the application is a new business requirement, there must be an IT process in place where users can request a new application. IT must have SLA's in place that allows them to assess the validity of the request, profile the application and deliver it to the virtual desktop in a timely manner (a few days to a week). Until the application is ready for delivery by IT, the user can continue to install or request a second virtual desktop (step 2 below).
2. Each user has the "ability" to self-service a second virtual desktop that can be used as a "playground".  Many power users have a need to install, test, evaluate different tools to make their jobs easier. Most users only need these applications for a few days or weeks, at least until a project is complete. Other users only need the application until IT is able to properly deliver the application into their corporate-delivered desktop.   This is where a second virtual desktop, i.e. a self-service desktop, could be requested. This is something like Brian recommended, 2 desktops. But the second desktop is only used if it is needed and requested through a self-service process. Of course because IT does not know what users will do to this desktop, proper security precautions must be taken into account.  With this option, users would have the ability to:
   1. Select the OS
   2. Select the life of the desktop (days, weeks or months)
   3. In the background, workflows are initiated that creates a new desktop, assign it to the user, and allow changes to be stored within the writable, user image.  When the timeframe expires, the desktop is deleted from existence.  

This option solves many of the challenges users experience in a virtual desktop world.  How to install temporary applications. How to use a new business application until IT is able to assess and deliver it properly.  

The point is that we must understand the users and their needs.  Most users can get along perfectly well with the applications delivered from IT.  But a sizeable portion of the user group needs autonomy, freedom, experimentation... A Playground. The one size desktop does not fit all.  Some user's might have two different desktops, others only 1.  We need to change the way we think about delivering desktops to users.  And in order to meet user expectations, we need systems (technical and process oriented) in place that can accommodate the users in a timely manner.

• Twitter: @djfeller
• Ask the Architect - Next-Generation site
• Questions - Then Ask The Architect
• See me talk about designing your XenDesktop solution on Citrix Live

Daniel - Lead Architect - Worldwide Consulting Solutions

With so many articles flying around about desktop virtualization and VDI, have you ever seen or heard of anyone actually implementing this solution? And even if you have, I bet you, like me, have many questions to ask.

Well, I've had the opportunity to sit down with Sandy Kingdon, a Dynamic Desktop architect for CSC. Sandy is working on a large XenDesktop implementation and I was able to speak with her about it. It is an interesting discussion and architecture in that it uses Citrix XenDesktop, VMware ESX and AppSense User Environment Management

• Current Capacity: 1,000 users
• End of Year Capacity plan: 10,000 users
• End of Project Capacity plan: 40,000 users
• Virtual desktop specifications: Based on customer analysis and experience
• Antivirus requirements and updates design
• Application integration with the user desktop images
• User-installed applications requirements and design
• End-point device configurations

This discussion was focused on the architecture, design considerations and experiences.  I can imagine as this project continues to grow to their 40,000 user goal we can have additional discussions on lessons learned, tips/tricks, etc. 

If you want to hear more and see what else we have going on around desktop virtualization architectures, I recommend you visit the Ask the Architect site. Also, if you or someone you know who is currently or already completed a desktop virtualization implementation, I'd be eager to hear from you.

• Sandy Kingdon (CSC) Podcast
• Ask the Architect - Next-Generation site
• Questions - Then Ask The Architect
• Twitter: @djfeller

Daniel - Lead Architect - Worldwide Consulting Solutions

When was the last time that a representative from your company's IT department spent an hour sitting down next to you and observed you while you were doing your work... for no other purpose than to learn about your needs and work habits so that IT can  provide you with better service, a better environment, and better application support?

Before you answer, I'd like to point you to a discussion on these pages that triggered me to think about this question: 

Daniel Feller authored a piece  which talked about the desire of users to install and manage their own applications in a virtual desktop environment. Dan gives several reasons that detail why letting users install their own apps in a virtual desktop is a bad idea in his opinion.

Brian Madden responded to some of Dan's points and stated that the flexibility and feel of control associated with user installed apps is critical to user adaptation of virtualized desktop environments. Therefore, Brian suggests providing each user with two desktops - one tightly managed by IT with approved applications; the other one more free-reeling to allow for any tool, utility, or app installed by a user. There are arguments for both sides and the common trade-off between user flexibility, IT's management capabilities, and cost must be considered during virtual desktop implementation projects.

So far, the virtual desktop discussion focused on increasing security through centralization and reducing desktop support and operating costs. Those are benefits primarily to IT. What about the users though? What's in it for them?

I spent several years in healthcare information systems, where the most valuable users (doctors and nurses, but especially doctors) are often the most reluctant to change their workflows towards the use of a computer and away from the voice recorder and paper notes that someone else has to decipher. How do you get these users to accept and embrace an electronic medical record (EMR) system? You have to state the benefit to them and let them experience them first hand! In this example  it means fewer patient deaths and complications due to missing or incorrect patient data and overall better patient outcomes. This appeals directly to some of the main reasons why these users are in their chosen field in the first place. Post implementation surveys among doctors and clinicians was overwhelmingly positive  once a doctor realized that she had the patients medical history at her fingertips and was more efficient in documenting her care.

Successful EMR implementation were all characterized by a fundamental shift in thinking in IT. Away with the old "this is not supported" argument of IT and away with the strict segregation of IT responsibilities between network, OS, servers, virtualized servers, databases, applications,  cross-system interfaces, storage, and "Citrix".  Our customer IT teams and we (the EMR software vendor) spent countless hours on the hospital floors, in emergency admission departments and in the operating room - simply to observe our users and provide the best possible products and the highest quality implementations to them. Our customer IT teams almost became experts in clinical documentation. On a side note, I am glad I wasn't on the OR team - I might have tossed my cookies...

Just like EMR implementations, virtual desktops have the potential of being disruptive and enabling at the same time. There is a fine line between providing a desktop from anywhere and excessively restricting capabilities. Successful implementations rely on strong leadership from the CIO down. Many EMR implementations include the Chief Medical Officer, CIO, Nursing representatives and traditional IT roles. By the same token, the virtual desktop initiatives must be guided by principles of including key user representatives and an IT organization that truly understands user needs. This should be understood at this point among many readers of industry commentary on desktop virtualization. However,  I still see many large organizations who make implementation decisions driven by their own organizational structure and  technical drivers (sometimes even politics). Of course, IT must enforce license compliance and protect environments from the hazards of poorly written software, but that imperative doesn't have to make it more complicated for users.

Back to the discussion between Dan and Brian:  I tend to agree with Dan - one virtual desktop image - centrally managed by a capable, agile, and results driven IT organization.  I simply don't want to switch between desktops for different tasks and I don't think I should have to. Instead, users who want their own apps demonstrate the business case (a personal preference of one browser over the other probably won't cut it) and an IT organization who understands their users' core requirements verifies the business need and provides the required app. Done. Simple.  

Going back to the opening question: When was the last time IT came to you? If you're in IT management or if you're a CIO - when was the last time you spent some proactive time with your users and learned about their work?

In the previous Provisioning Services High Availability Considerations blog, I briefly spoke about using Provisioning Services 5.1 with read-only shared access to a SAN LUN(s). Now I will provide a step-by-step overview of how to implement this feature.

Let's start with pre-requisites that I mentioned in my last blog:

• You need to install Microsoft iSCSI initiator on all Provisioning Services servers that access the SAN.
• Private Image mode is not supported.
• If cache is located on server disk, a separate shared storage location that has read-write access is needed for write cache files.

Steps on the SAN:

You will need to create a volume on the SAN interface front end and then set access type for the volume to read/write, later you will make the volume read-only through NTFS attributes. In my example, I will use NetApp, your case might be different. The storage devices are called iSCSI targets and the clients are called iSCSI initiators.
 
Make sure it is online:

Now we move to the Provisioning Services server:

Initially, you will need to use iSCSI Initiator to login to the SAN volume on only one of the Provisioning Services server while in read/write mode. If you are using Windows Server 2008 the iSCSI software Initiator and components are built into the OS, if using Windows Server 2003 iSCSI software Initiator is available as a download package from the Microsoft website. In my example I am using Windows Server 2008, so I just enabled the service from the Admin tools.

 
Depending on your settings you may get a UAC warning, go ahead and approve. The iSCSI Initiator is our Provisioning Services server; under the general tab you will see the Initiator Name that you will need to provide as "Initiator" to your SAN. 

Go back to your SAN and add the "Initiator Name" to Initiator group:

Back to your Provisioning Services server, from the iSCSI Initiator Properties you need to go to the Discovery tab and add the portal by specifying the IP address to the iSCSI target:
When the LUN first appears on Windows you will have an uninitialized volume, therefore you have to switch it Online and let it get initialized. Next step you need to do is format the volume:Once you formatted the volume and assigned a drive letter/mount point, next step you will copy all the vDisk image files (.vhd) and associated properties files (.pvp) to the volume, no need to copy the Lock files. Before you copy the files, make sure all properties for the vDisks that will reside on the volume are set correctly (including High Availability).
Next step is to make the volume read-only. You can use diskpart.exe, verify the volume number, select it and then set the attribute to read-only. In case you want to verify if it was set correctly you can type "detail volume" and verify that "Read-only" is set to "Yes".

Now you will log off from the volume on that one Provisioning Services server, from the iSCSI Initiator click on "Details" and then" Log off..."

In case you get an error message about the volume being in use, go to Disk Manager and switch that disk Offline.You will log on to the target again and make the volume a persistent target.  You must log off and then re-login to the volume to get NTFS on the server to re-read the volume attributes, so that it will recognize the volume as read-only. Making the volume a persistent target will ensure the volume is accessible when the server reboots: 

Just mount the iSCSI volume on all the other Provisioning Services servers; it is now safe since the volume is set to read-only. Also, in order to facilitate your job, have all servers to mount the volume using the same drive letter or mount point; if not you will need to adjust that from the Provisioning Services Console. You should be all set after creating a store and pointing the Path to the SAN volume and adding the vDisk to the pool. Don't forget if you are using Difference disk mode you must enter a default write cache path for the store that does not point to the read-only SAN volume, this also applies if you are going to use write cache on the PVS server (cache on server disk).

You might be thinking, what if I am using a NetApp array as the back-end storage attached via Fibre Channel? There is no reason why this should not work since the LUN appears as a drive to Windows, so Provisioning Services should have no problem using it. When using Fibre Channel the iSCSI initiator is not required, so vendor specific software for the FC device should be used.

If you want more details about this subject, I encourage you to watch this TechTalk session called:  "Simplifying Implementation of Provisioning Services"

"Elisabeth Teixeira - Principal Engineer - Worldwide Technical Readiness

Follow me on Twitter: http://www.twitter.com/lizteixeira

Follow me in the Blogs: http://community.citrix.com/blogs/citrite/elisabetht

Some of the questions I've received lately is how to design a large-scale, enterprise XenDesktop architecture.  We all can attest that most systems put into place become much more difficult to architect as the number of users increases.  I'm not talking about Citrix products, I'm talking about any product.  Which one do you think would be more difficult to design:

• A 100 user (insert your own product here) environment
• A 10,000 user (insert your own product here) environment
• A 50,000 user (insert your own product here) environment
  

Most of you will probably agree that it gets quite a bit more difficult as the number of users increases.  And if we do a typical type of design, I would tend to agree, but I'm thinking we can simplify this so even the 10,000 and 50,000 user XenDesktop environment can be as easy as a 100 user deployment. 

Many of you are probably thinking, this guy is full of it, he is too pie-in-the-sky for me.  And when I first started thinking about this simplified architecture, I tended to agree. But as I've continued looking into this and discussing with other architects, I've come to the realization that I might be on to something here.  See for yourself in the following video.  I plan on posting additional videos around this concept in the future to show/demonstrate how it would work.  But for now, I bring to you the Pod concept (and don't forget to leave your comments) 

Daniel - Lead Architect

Follow my Blogs: http://community.citrix.com/blogs/citrite/danielf

Follow me on Twitter: @djfeller

Send Desktop Virtualization questions to: AskTheArchitect@Citrix.com

Watch previous Ask The Architect Videos at: http://www.citrix.com/tv/#video/1063 

As we now have the desktp virtualization design discussion going, I want to look at the next big question... Should I do XenApp or XenDesktop? Can I get by with Terminal Services or do I need VDI? Spend just a little time going through tweets, blogs and articles related to desktop virtualization and you will be left in the same place you started, asking the simple question "Should I do this or am I crazy?"  When I think about the desktop (I really need to have a better imagination) it isn't focused on what solution to pick, or which vendor to pick... It is focused on one simple concept:

Delivering the Correct Application to the Correct User in the Best Manner Possible

• What is the correct application? The one the user wants
• Who is the correct user? The one making the request
• How should it be delivered?  That is the tricky question isn't it.  This is where we all struggle to make headway, we keep stalling because we just aren't sure.  Why is the decision so difficult? Because users are very demanding. User keep the organization functioning.  If you hurt the user, you hurt the organization, which means you will hurt yourself (bye bye promotion, raise, or job).  
  

So how do you make the right decision? By realizing three simple truths:

1. One size does NOT fit all
2. Applications are unique
3. User's requirements change
   

Trying to align the users, applications and devices into a single, coherent desktop virtualization solution seems like a daunting task, but if you follow a few guidelines the process is doable.  For example, if a user comes to work with their own personal laptop, can I simply deliver them a hosted virtual desktop or will they need a local virtual desktop? What about users with a 3-4 year old PC?  What can I do with that setup? 

This is why I suggest you take a look at the following, recently published, white paper focusing on the deciding factors between VDI and Terminal Services-based solution. If you want a highlight of the article, it is that the whole debate is not even a debate at all. 

What do you think? 

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
  

After my first blog, I received a few comments focused about user-installed applications and how there isn't much talk about them.  Faisal posted a comment that stated he was doing a pilot with XenDesktop.  Right now the biggest complaint is that users can't install their own "personal" applications  and this is one of the big questions regarding virtual desktops.  We had a few comments from others wanting to know the same thing (some really good posts). Well, here are my thoughts

With a physical desktop model, users could essentially do just about anything to their workstation.  How much of a good thing was this?  It makes the user happy, but what are the associated risks? 

1. Managing the endpoint became a nightmare. Hard to know what application conflicts will ensue with these unknown applications.
2. Introduction of viruses, malware, spyware, etc.  Many of the applications users install are freeware/shareware from untrustworthy sites.  If it is on the desktop, does it now have the freedom to inflict damage to the rest of the network?
3. Workstations became bloated and eventually slowed to a crawl resulting in IT having to completely rebuild the workstation.
   

Let's now move to the desktop virtualization model.  If we are using hosted virtual desktops, that typically means the desktop is now operating within the confines of the data center.  If you allow users to install applications onto their hosted virtual desktop, in my opinion, you might as well just open the doors to your data center and let anyone in because that is what you are doing if you let users install anything.  Doesn't that concern you?  If not, try telling this to a security person within the organization. After they recover from their stroke, they will tell you why this is not a good idea.

Now I'm not saying that we can't and shouldn't allow user-installed applications, I just want to make sure everyone understands the risks with doing such a thing.  With the 3rd party solutions that are out there (AppSense and Atlantis Computing were mentioned in the comments from a previous blog post), my question would be

1. How do we protect the data center from unknown apps.
2. How do we keep the virtual desktop optimized and supportable. I don't want manage more bloated desktops By the way, this makes a great case for a Bring Your Own Computer (BYOC or BYOPC) model.
   

I do just want to add one more point.  I've been using a hosted virtual desktop for about 2 months now with a shared disk, so any changes I make (application installs) go away after reboot.  Truthfully, I haven't had much of a problem.  I did need to download and install a few freeware tools to help me finish a project, but I only used those items for about 2 hrs.  The nice thing, in this instance, was after I rebooted, they were gone.  I don't plan on using them again. And if I do, I'll just re-install. Of course this isn't an application I need. 

So the final question is should we really allow user-installed applications to persist or should we have a process in place where IT can quickly virtualize and deliver these applications to the respective users through a standardized application delivery approach?   

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
  

What's new in desktop virtualization?  Well, lots of announcements from different vendors trying to peddle their wares, but I haven't seen or read anything very thought provoking. 
<rant> (Man, I'm totally geeking out here)

I'm trying to keep abreast of the latest happenings in the desktop virtualization space from a design and architecture perpsective, but honestly, there isn't much.  There are tons of solutions out there, some better than others. There are many point solutions out there that solve 1 issue for desktop virtualization.  Heck, even Brian Madden commented about the one-hit wonders in a recent blog. 

I'm also on twitter (@djfeller) and I try to follow VDI/Desktop Virtualization, I have Google Reader alerts setup (You can follow my shared items but there isn't much I've found useful). What do I typically see? One post about a new feature, then I see it retweeted a zillion times (Ok, I'm exaggerating a little, but still).  I see articles about why companies aren't doing the VDI/Desktop Virtualization thing yet.  Why? It's not because there aren't solutions. There are. They might not solve every use case, but they can solve some for some users. So what's the holdup?   No one is showing them how to get it done. 

It's time for a REAL discussion. Let's start focusing on designing a desktop virtualization solution.

</rant>

I'm not going to lie to you and tell you desktop virtualization is easy. It won't be a walk in the park unless your park is full of mountains, rivers, mosquitoes, coyotes, wolfs and bears.  So, why would we attempt to do something like this? Because the alternative is even worse. With so many different user requirements you can quickly see how the current distributed desktop environment is a disaster waiting to happen (or already happened over and over again).

But let's not dwell on the ugliness of the current model. Let's instead focus on designing a better solution.  Let's start talking about design, and my oh my there is a lot to talk about, which is why I'm about to start a blog series on designing a desktop virtualization solution with XenDesktop.  I plan to focus on the main design decision areas and giving you my thoughts and recommendations based on what I've seen so far. I'm positive many of you have seen different things, which I encourage you to comment so we all can learn. 

This should be a great series and I can't wait to hear some of your comments.  (BTW, I got a lot of great comments for all of you during our Provisioning Services for XenApp blog series and hope to get the same level of feedback.)

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
  

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:

1. Deciding between VDI and Terminal Services
2. Designing a desktop virtualization solution with XenDesktop
3. 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)

• Recorded Webinar
• PowerPoint

Part II: Designing a desktop virtualization solution with XenDesktop

• Recorded Webinar
• PowerPoint

Part III: Migrating users from physical devices to virtual desktops

• Recorded Webinar
• PowerPoint

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. 

1. XenDesktop Controller: CPU intensive during logons and hosted virtual desktop startup (RAM and Network underutilized)
2. 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

Do you have a desktop virtualization design or architecture question? Then Ask the Architect

What is it?

Many times when people are looking at a solution or trying to create a design, they have a question as it relates to their environment.  Although there are numerous documents and best practices on the Citrix knowledge base, many of these are based on a "recommended architecture" which typically does not look like many of your environments.  This is where Ask the Architect comes in.  If you have a question regarding your desktop virtualization project, send an email to AskTheArchitect@Citrix.com.  (HINT: Make your questions short and to the point.)  Based on your email question, we will strive to find you an answer and post a video on CitrixTV (because many other people will have similar questions).  The answers will be brief and to the point, less than 5 minutes (we don't want to bore you and we still have lots of other things to do too).

What it is not?

The desktop virtualization Ask the Architect is not a way to get a complete desktop virtualization design. For a full-scale design, I would recommend you get in touch with Citrix Consulting, who have already been instrumental in designing some of the largest desktop virtualization solutions. It is also not a troubleshooting forum, as there are already many forums for those items (plus I've never heard of any Citrix products having issues )

Who is Ask the Architect? 

This is a big question. You don't want to send in an email and have it answered by a marketing or sales person who tells you to buy another product. You want someone who has designed complex solutions.  This is why Ask the Architect is not 1 person, but many.  Based on the question submitted, the most experienced Citrix Architects from our Consulting organization will create an Ask the Architect video post and submit it to CitrixTV for all to see. 

How to Get Stared?

Start watching the Ask the Architect series on CitrixTV.

• Episode I: VDI and PVS for Multiple Remote Sites: http://www.citrix.com/tv/#video/882  

Email: AskTheArchitect@Citrix.com
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

When Citrix XenDesktop is brought up in conversation, it is most often in reference to being deployed with a virtual desktop infrastructure (VDI) solution. But XenDesktop is not limited to delivering only virtual desktops - XenDesktop delivers an exceptional user experience with physical desktops just as well. In fact, organizations still utilize physical desktops instead of virtual desktops for niche roles, such as for dedicated, resource-intensive applications like computer-aided design (CAD) and financial trading. Blade PC hardware is often chosen for its benefits in satisfying security requirements, providing desktop hardware consolidation and in serving as a dedicated, high-performance machine. As we discuss in this post, XenDesktop is a perfect pairing for a Blade PC environment and our design considerations whitepaper provides information to IT professionals seeking a smooth deployment.

In this XenDesktop on Blade PCs Design Considerations whitepaper, we provide our experiences from implementing XenDesktop on HP Blade PC hardware within the Worldwide Consulting Solutions lab at Citrix headquarters in Ft. Lauderdale. Within the document, you will find topics such as: 

• The direct applicability of key components of XenDesktop Platinum to Blade PCs, including XenApp, Provisioning Services and EdgeSight for EndPoints.
• A high-level architecture describing the Provisioning Services streaming process to Blade PCs and user access to the XenDesktop environment.
• Setup considerations and configuration information for implementing each XenDesktop component, including the Desktop Delivery Controller, the various Citrix desktop clients, Provisioning Services vDisk creation, management of a Blade PC environment, and more.
• Other in-depth, technical tips for administrators setting up and working with XenDesktop on a Blade PC environment.

Citrix XenDesktop already comes with Blade PCs from vendors. Try out additional XenDesktop features on your Blade PCs and experience the clear benefits for your organization.

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

Provisioning Services High Availability Considerations - Part 4

In the previous Provisioning Services High Availability Considerations blog, I spoke about placing your vDisks on a Network Attached Storage (NAS). Now I will talk about placing your vDisks on a Storage Area Network (SAN).

Placing your vDisks on a Storage Area Network (SAN) - iSCSI

Using a SAN to store the vDisks and access it by means of the iSCSI protocol provides a reliable way with good performance at a moderate cost to purchase, implement and maintain. This solution will provide highest levels of reliability.

What should we consider with this solution?

• Requires software to manage the storage array.
• iSCSI Initiator and MultiPath software must be installed and configured on each PVS; iSCSI Target software must be installed and configured on the File Server(s).
• A Cluster or Parallel File System is required to ensure the integrity of the partition/LUN containing the vDisks.
• I/O for vDisk input (loading from the share) and vDisk output (delivering to the Targed Devices) is handled by the same network link.

What are the recommendations?

• NIC - teaming should be used to increase the reliability and the I/O between the Provisioning Servers, File Server and Target Devices.

Dedicated NIC - teams should be used for loading the vDisks and for delivering the vDisks to the Target Devices.

Placing your vDisks on a Storage Area Network (SAN) - Fibre Channel

Using a SAN to store the vDisks and access it by means of Fibre Channel provides a very reliable way with the highest levels of performance and reliability at highest cost. This solution will provide high degree of scalability to support increasing number of Target Devices.

What should we consider with this solution?

• Additional Hardware (HBAs) required for every Provisioning Server.
• Requires software to manage the storage array.
• A Cluster or Parallel File System is required to ensure the integrity of the partition/LUN containing the vDisks.

What are the recommendations?  NIC - teaming should be used to increase the reliability and to I/O between the PVS Servers and the Target Devices.

Normally using a SAN for vDisk storage with Provisioning Services requires that a shared file system be placed in front of the SAN to coordinate multiple server access to the NTFS formatted LUN(s).  Using Provisioning Services 5.1 you can use a SAN without a shared file system in some instances (you can have "read-only" vDisk storage). The desired boot modes for PVS target devices are important when using this feature since Provisioning Services only allows read-only shared access to the SAN LUN(s). Let's see what are the main considerations when using this new feature:

• You need to install Microsoft iSCSI initiator on all PVS servers that access the SAN.
• It is only for Standard Image mode, Private Image mode is not supported.
• If cache is located on server disk, a separate shared storage location that has read-write access is needed for write cache files.

I encourage you to attend this TechTalk session called:  "Simplifying Implementation of Provisioning Services"

Hope to see you there on Thursday, August 27, 2009 at 1:00PM eastern time.

Elisabeth Teixeira - Principal Engineer - Worldwide Technical Readiness
Follow me on Twitter: http://www.twitter.com/lizteixeira
Follow me in the Blogs: http://community.citrix.com/blogs/citrite/elisabetht

Big discussions are happening in August and will you be part of it?  Over three days in August a XenDesktop Ask the Architect TechTalk series will be delivered focusing on analyzing, designing and implementing a VDI solution. 

This particular series is focusing on the questions I hear over and over again: # I'm interested in VDI but I'm not sure where to start?

1. I already use XenApp but don't know if and when I should be using XenDesktop instead.
2. I've decided to go with XenDesktop as my VDI solution, but how do I design the environment correctly?
   

I believe many of you have similar questions.  Instead of answering these questions on a one-by-one basis, we've decided to do an Ask the Architect TechTalk series. 

Part 1: Virtual Desktops or Virtual Applications: Selecting Your Best Solution*(August 11 @ 1PM EDT)*

We've heard the debate from numerous people across numerous platforms... Should I use TSE or VDI for my organization? When should I use XenDesktop if I already have XenApp?  What type of virtual desktop do my users require? What options do I even have?

This is a big question and one that deserves the entire time. I encourage you to attend this session as it sets the stage for the rest of the week. If you can only attend one session, then this is the one to attend.

Part 2: Creating an Enterprise VDI Solution with XenDesktop (August 12 @ 1PM EDT)

Once you decided to use XenDesktop as your VDI solution, how do you create your enterprise design?  Would you believe there are essentially 4 things you need to know in order to create your XenDesktop design?  Based on those four items, you can design the entire infrastructure.  We will cover the design decisions for# Virtualization Infrastructure

1. OS Delivery
2. Application Delivery
3. Desktop Delivery
4. Virtual Desktop Design
   

Part 3: Successfully Migrating Users to Virtual Desktops(August 13 @ 1PM EDT)

Once the environment is designed and built, its time to move users over to the virtual system.  The cutover needs to be smooth and seamless for the users or else they will need to recreate their entire personalized desktop environment. This will not only take time, but will also give the users a bad first imipression of the overall solution. 

This TechTalk session focuses specifically on how to migrate user environments into the virtual desktop world. It will cover the options, ramifications, and approaches. 

This should be a great series with lots of good information. Hope to see you there!

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