XenDesktop 5 Deep Dive: Machine Creation Services (MCS) on vSphere 4.1

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As promised, I have published my Deep Dive around MCS over at The GenerationV Site: http://tinyurl.com/4tzpfts. Check it out!

The data is abstracted, but all the source came from a real-world pilot. The question posed was, "What is the impact of MCS on storage and how exactly does it work on vSphere?" So, I rolled up my sleeves, dug in, and figured I would share my findings.

In short, MCS works as design and can greatly save on storage space by using a linked snapshot as well as save on administration by rapidly deploying machines. The downside becomes when you need to move machines to different storage. Not always a common event, but one to consider.

Personally, I still prefer PVS for an enterprise-scale deployment, but MCS has it's place.


Other resources:

• XenDesktop Design Handbook Success Kit  - One stop shop for XD Resources
• Citrix XenDesktop Architecure Series  -  Citrix Community Blog for XD Architecture
• Dan Feller's Blog- Great Architectural Resource for XenDesktop

Joining GlassHouse Technologies!

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I'm happy to announce that I have joined the team at GlassHouse Technologies as a Senior Virtualization Consultant. With this role, I will be tasked with helping manage virtualization projects, with a main focus on Citrix Technologies.

My main focus will be on expanding our XenDesktop / Virtual Desktop offerings, and will leverage all of our corporate expertise on Datacenter Management, Virtualization, Storage and Security.

Citrix closes the gap with VMWare -- XenServer 5.6 Beta, Part 1

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Most of the complaints I've heard in regards to XenServer vs. VMWare is the fact that XenServer does not allow an overcommitment of memory.  If you have a host server with 16 GB of RAM, you can only allocate up to 16 GB of RAM for the guests (yes, I know, technically less since Xen requires some resources... but you get the point).

Personally, I'm not a fan of over-allocating memory.  I actually like that with XenServer, I do not have to worry about it.  I've seen too many VMWare farms suffer because of assigning too much memory then having to constantly swap resources.  I think if you engineer the solution correctly, and size your servers properly, memory allocation should be kept in check.

However, seeing this as a fault when comparing virtualization host platforms, Citrix has released the latest Beta of XenServer 5.6.  One of the new features IS allowing your to over-allocate memory... they call it Dynamic Memory Control.  I have to admit, it is pretty cool and very easy to use.  The XenCenter display makes it VERY intuitive... all the better to see WHERE your resources are allocated, especially when squeezing memory.

 
To read more technical details, see my full article at: http://www.thegenerationv.com/2010/04/xenserver-56-preview-part-1-dynamic.html

Optimizing XenApp on VMWare ESX

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There are numerous benefits for running Citrix XenApp on XenServer; including single vendor support, built-in optimizations, and integration features. However, what if you are working in a VMWare ESX environment? As a consultant or an internal engineer, you cannot always dictate the virtualization environment. The following are some tried and true best practices for optimizing XenApp on VMWare ESX.

Read More, view the full article at GenV: http://www.thegenerationv.com/2009/10/optimizing-xenapp-on-vmware-esx.html

TheGenerationV.com

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I'm happy to announce that I am joining the team over at TheGenerationV.com.

I will still be maintaining my personal blog here as time allows, of course, but will also be writing case studies and analysis articles for GenerationV.

TheGenerationV.com is dedicated to hosting discussions and technical articles about next generation technology. TheGenerationV.com was founded on July 10, 2009 by Rick Rohne, however, it is made up of some of the most talented Systems Integrators in the country.

I'm looking forward to sharing my thoughts on virtualization with this team of engineers. Please come check it out.

Quest vWorkspace

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Some time back, Quest Software purchased Provision Networks. They have sense re-branded and re-released their Virtual Access Suite (VAS) product line as vWorkspace.

Latest and Greatest: My Citrix on VMWare

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This may be my last entry on Citrix/VMWare for the time being.

After 1 month of production runs, our 1 vCPU 2GB RAM VMs are churning nicely, averaging around 32 concurrent users. Running at 10 VMs per DELL 2950 Host, we see that Host Memory is stable, Host CPU is well utilized. There is enough capacity that another 2 VMs could potentially be added with no adverse effects, netting approx 380 users per HOST... solid density.

Rolling out updated Citrix VM Template

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I have updated our Citrix VM Template:

• Added CD, left disconnected
• Updated Tools, included Memory Manager (aka Balloon Driver) -- after reviewing this time and again with various engineers, I have come to several conclusions:
• a lot of the info out there is still based on ESX 2.x
• The Balloon Driver is a safety net, which should not be normally called
  on when designed properly
• when in doubt, and until proven otherwise, go with the standard package
• Tweaked the service controls
• Added PowerShell 1.0 (I'm becoming a big fan of PS scripting)

More on Citrix Load Evaluators

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Well, most of feed back I received from other industry players confirmed my initial suspicions... counters based on Windows Perf Counters where Windows is a VM are not reliable. A local area architect, who is not married to any one technology, summed it up nicely:

"You have touched on something that is inherent to the virtual world: the performance counters are always wrong. Exactly how wrong, that is debatable. In the past, I have used empirical numbers to control load. That means keying off of something like user count, memory utilization, or page swaps. It isn't an exact science, but some testing should give you the right mix."

Citrix Load Evaluator Rules in a VM

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I mentioned in my previous post that one of my VMs was pegging at 100% of the vCPU, but the Windows Task Manager was showing only spikes (although a lot of them), and my Citrix load value for that server was in the 7200 range. Of course, the system was crawling and unusable for customers.

Update on My Citrix VMWare Machines

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Ok, if you have been following my blog, you know I have been researching and building the best possible Citrix VMs to run on my ESX Hosts. Granted, XenServer might be better for XenApp, but we work with what we have, and I have ESX 3.5.

I currently have 4 production VMs running, 2 in each production Zone. The first two in DataCenter1 went live about a month ago... and churn nicely. They will routinely show a load evaluation of 10000 (Full Load), and the 1 vCPU Utilization is fairly high (based on vCenter stats), but no complaints from users. Initial test = PASS.

Updates on ESX Templates and Citrix on VMWare

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From my previous posts, you can see I am digging in on ESX best practices, specifically for Terminal Services/Citrix.

I will be posting an updated white paper, entailing my best practices, methods, and results soon.

However, in the mean time, Project VRC is now LIVE. Great info comparing ESX, XenServer, Hyper-V, and Bare Metal. According to their tests, they recommend 2 vCPU instead of 1 vCPU... and they present a compelling argument.

For now, I am moving forward with 1 vCPU and 2 GB RAM to start a baseline, but will add a 1 vCPU 4GB RAM and a 2 vCPU and 4GB Ram for comparision. I'll include the results in my summary paper once it is available. If you want the prelim finding, just email me.

In the meantime, check out Project VRC

Creating and Deploying a Citrix Template on VMWare ESX

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Similar to my other related posts, this is specific to my operating environment and may not fit all. However, the best practices referenced here should help in most environments.

Citrix on VMWare ESX

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Although these guidelines are created using the following environment, these standards should apply to just about any Terminal Services-based virtual environment (XenApp 5, Quest vWorkspace 6, 2X, Windows 2008 TS, etc.):

• VMWare ESX 3.5 Update 2
• Virtual Center 2.5
• Windows 2003 R2 SP2 Standard Edition
• Citrix Presentation/XenApp Server 4.5

ESX Virtual Machine Best Practices

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My primary focus is server-based computing, specifically Citrix Presentation/XenApp Server. With a stronger push for virtualization in most market segments, I've seen mixed results for virtualizing Citrix on VMWare.

Several vendors and consultants have recommended using XenServer (now from Citrix, formerly from Xen Source) which is better at handling XenApp workloads. My question as been, WHY? What are the key differences and why the performance difference? The key is Memory Sharing and how VMWare allows overallocation of resources.