If you haven't noticed, XenApp 5 Feature Pack 2 has been announced and with it comes the new Power and Capacity Management feature. By now I hope you downloaded the Tech Preview release or at least had a chance to watch these videos which explain the feature in detail (How it works, Tech Talk recording, my interview on it, our architect Juliano's interview on it).

The following are the enhancements we made to Power and Capacity Management since we released the Tech Preview version.

• High availability for concentrator
• We now support both physical and virtual servers in the same workload group
• In determining the maximum session capacity of a server, the system now takes the lowest of what the administrator has set or what the load evaluator computes based on the current load
• In addition to SQL Server 2005, we now "officially" support SQL Server 2008
• Minor visual enhancements

Juliano and I will be blogging further on these to clarify what these enhancements are and to offer up other deployment considerations. Stay tuned to the XenApp 5 Feature Pack 2 blog roll for more information beginning next week Monday.

And thanks to all of those who participated in the technology preview and provided feedback. We can't tell you how critical it is to us. Speaking of which, we invite you to pre-register for the Windows Server 2008 R2 Technology Preview coming sometime next quarter

Learn more about Citrix XenApp 5 Feature Pack 2

• Official Press Release - http://citrix.com/English/NE/news/news.asp?newsID=1857726
• XenApp 5 Feature Pack 2 release Web Site - http://citrix.com/xenapp/featurepack2
• XenApp 5 Feature Pack 2 Executive Video - http://citrix.com/xenapp/fp2/video
• XenApp 5 Feature Pack 2 Release Webinar - http://citrix.com/xenapp/fp2/techtalk
• XenApp Expert Series videos for this release - http://citrix.com/xenapp/fp2/expertseries
• XenApp 5 Feature Pack 2 Blogs- http://community.citrix.com/blogs/tag/xa5fp2
• Download XenApp technology previews - http://citrix.com/xenapp/techpreviews
• XenApp Product Page - http://citrix.com/xenapp/

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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.

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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.

Don't forget to register for next Thursday's (July 23rd, 1-2pm EDT) TechTalk on XenApp power and capacity management. We will not bore you to death with slide ware. Majority of the presentation will be a live demo with lots of time for Q&A. You will learn

• How to better manage your XenApp capacity (and subsequently save some power as well)
• How to simplify XenApp server maintenance (software patching etc) by understanding how capacity management does load consolidation
• How this feature can simplify migrating users to new XenApp server farms
• And how easy it is to implement this solution in your "existing" XenApp server farms

We've recently announced a cool new feature for XenApp, called Power and Capacity Management (PCM). Here's a video demonstrating PCM in action:

Architectural Overview

Power and Capacity Management uses an agent/manager architecture. The agent is installed at all XenApp servers you wish to power manage. The manager - called the Concentrator - is responsible for monitoring, storing data, and issuing power operations to the agents. The Tech Preview doesn't have high-availability implemented yet, so you should install only one concentrator. In the final version you can have multiple concentrators to enable high availability. Another thing to note is that we've decided to implement Power and Capacity Management outside of XenApp IMA (Independent Management Architecture) partially because we wanted PCM to manage multiple XenApp farms. You can install the PCM concentrator alongside your Data Collectors if you only want to manage a single farm.

Installation and Communications

During agent installation, you will be asked for a farm and workload name. The concentrator manages a single Power and Capacity Management farm - note that this is not the XenApp IMA farm name, it's just a namespace for PCM. This setting is stored at HKLM:/Software/Policies/Citrix/XenAppPCM, which is good if you want to install the agent using dummy data and then use an ADM/X file and Group Policies to manage this setting across multiple XenApp servers later on. We plan on integrating this configuration into the XenApp configuration interface and SDK's as well.

The other configuration setting for the agent is the workload name. This represents a server silo or group. All configuration for Power and Capacity Management is related to a workload, so you want to make sure all XenApp servers in the same workload have similar or even identical configuration. You can also define tiers of servers within a workload, telling PCM which servers should be powered on first, and which ones to power on only when necessary.

Once you install the agent on your target XenApp server(s), it will register with the concentrator and its defined workload group will automatically appear in the PCM console. This is possible because the concentrator creates a Service Connection Point (SCP) under the computer Active Directory (AD) account during installation. This is done using the computer network account, so no special AD authority is required. The agent queries AD for these SCP to find the its concentrators. Since all PCM communications are Windows Communication Foundation (WCF)-based, all power-managed XenApp servers computers must be in the same domain as the concentrator that is controlling the farm they are joined to.

Configuration

Before Power and Capacity Management can manage the servers you've added to the workload, you need to enter the server capacity and policy schedule. The server capacity is related to the Load Evaluator, but they don't have to be the same. You will enter how many sessions are expected for each "hardware specification" in the workload. The hardware specification is automatically displayed when the agent registers, you just have to enter the capacity value. This setting is used to calculate the "session buffer", i.e., how many new sessions are currently available on the workload. If you under-estimate this number, then PCM will start more servers than necessary. If you over-estimate this number, PCM may not realize that the workload is running out of capacity. The Tech Preview version requires this manual configuration, at product release we plan to introduce some automatic adjustments to simplify this configuration.

The last piece of configuration is to define a policy schedule. You will enter the policy configuration and how it will vary during the day and throughout the week. The policy defines the minimum number of servers that must be online and how many spare sessions to maintain. Spare sessions are calculated as the difference of the workload server capacity and the number of connected sessions. Spare sessions are a buffer of capacity. The higher the number, the more idle capacity you will have on your servers. this is good when you have a very active user base or during times when many users login very rapidly. The lower the number the less idle capacity you will have. Setting the number too low may result in reduced performance or response while users wait for additional capacity to power on.

That's it! Now select the workload and "Enable Power Management" and PCM will start enforcing the policy schedule. You might notice that some servers power down immediately. That is normal operation if the current policy settings require less capacity than what is currently powered on.

Stay tuned for more posts from me on Power and Capacity Management. In the coming days and weeks, I'll go in depth on more advanced features like load consolidation, SDK's and some interesting possibilities that are afforded to us and that we are considering developing with PCM.

Download the technology preview of power and capacity management at the XenApp Technology Preview Center. Also, stay updated by following XenApp on Twitter.

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

What if, you can dynamically scale up or scale down your XenApp servers based on user load? What if, you could avoid over-provisioning your XenApp servers but also meet the occasional peak capacity demand? What if, you can consolidate XenApp user sessions on fewer servers to reduce power consumption and simplify server maintenance? These are the type of questions we heard from our customers and partners that led to the creation of XenApp Power and Capacity Management feature. The Technology Preview is available now and you can evaluate it on Presentation Server 4.5 and XenApp 5 releases.

So, how does it work? XenApp administrators can define server workloads/silos, specify the capacity requirements for each workload and sit back to watch the system automatically consolidate sessions across fewer servers, power up servers as needed and power down idle capacity. Or, admins can just turn the light off when no one is home e.g. create a simple schedule to power on servers at 8 am in the morning and power them down at 7 pm in the evening. Try it out and let us know.

Watch my Citrix TV video showcasing this technology at Synergy 2009. We think this technology will play a key role in our vision towards autonomic farm management and would like to hear more from you. Check out the Tech Preview and give us your comments/feedback. You can use the support forum for any technical issues with this release.

NOTE: For this Tech Preview release, we are supporting Wake-on-LAN power control for physical servers and using the XenServer API power commands for XenServer virtual workloads. We do support Microsoft Hyper-V and VMWare ESX for load consolidation but this Tech Preview release does not support power management for these virtualization platforms.