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RealTime - Questions: "I own a Windows xp desktop computer fully patched with 4 gigs of ram and a 500 gig hard drive.?"

Wed, 01 Dec 2010 13:41:45 GMT

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re: Does OS "tuning" help VDI performance? (Part 1)

Paul Wilson — Thu, 07 Oct 2010 22:35:49 GMT

To emaxt6's point, Citrix actually includes an optimization tool in XenConvert and the Provisioning Services Image builder. Also, as Daniel pointed out above, Jonathan Bennett (of AutoIT fame) has released tool that generates a VBS script to optimize the Windows 7 environment which I find is great for optimizing via Logon scripts.

re: Does OS "tuning" help VDI performance? (Part 1)

Paul Wilson — Thu, 07 Oct 2010 22:13:26 GMT

I think the goal of optimizing the guest OS is to improve the user's perception of the virtual environment. Users may not always notice a 9% improvement, but they sure do notice a 9% degradation. The vendors are always looking for ways to optimize the memory and CPU usage on the hypervisor and they will continue to do so. But sometimes, like edgeseeker points out, optimizing inside the guest is still an area where improvements can be made.

I believe the optimizations to implement will be dependent on the applications being virtualized. Consider that some optimizations are specific to a particular application like Internet Explorer's "Force Offscreen Compositing" setting. When that IE setting is not enabled, the users see a lovely blinking effect when some pages load in a remoted environment. Enabling that setting may not change density per server, but not enabling it will result in the user's perceiving the VDI environment to be unusable. I bring this up to point out that such tests may not benefit from generic optimizations or may not change CPU/RAM consumption on the host, but in the real world they could be the difference between a successful POC and a lost opportunity.

As amply discussed above, some optimizations improve other performance metrics such as IOPS and in and of themselves can provide a cost reduction by saving storage costs. I believe that storage response time has the greatest affect on user perception, more so than CPU or even RAM in some cases - probably because despite the move to virtualization many applications and operating systems still make assumptions around the storage being local and fast. Targeting storage related optimizations and software should be at the top of our list for improving user experience. Storage is such an integral part of the user experience those optimizations almost always make sense.

I guess all said and done, I would still recommend optimizing the OS where it makes sense. You may not get any more users on the box, but you get happier users that adopt the technology and recommend it to their friends and we all benefit.

re: Does OS "tuning" help VDI performance? (Part 1)

Daniel Bolton — Mon, 27 Sep 2010 12:11:50 GMT

@Smcpartin

blogs.technet.com/.../optimising-windows-7-images-for-use-in-vdi.aspx

It's free - doesn't have everything yet but it's a good start.

Dan.

re: Does OS "tuning" help VDI performance? (Part 1)

Sean McPartlin — Mon, 27 Sep 2010 00:19:20 GMT

I am still testing what optimizing can do for my cuurent hyper-v environment. (I hate vmware) But from tips to optimize vm os's to the tools vendors have to reduce iops or storage footprint I think it's a better practice over doing nothing.

Maybe a low cost tool to make all the other tips and changes these blogs recommend. Most people who say they don't think its worth it because they are lazy. If there was a tool I think people would lock on to it.

The accelerators, optimizers and storage tools all seem to make an impact for sure.

re: Does OS "tuning" help VDI performance? (Part 1)

emaxt6 — Fri, 24 Sep 2010 18:14:11 GMT

I think that VDI vendors should include an integrated tool (with the agent or similar) to automatically disable/enable services/features as requested at least for common VM desktop like XP or 7.

This to consolidate optimization and best practice.

re: Does OS "tuning" help VDI performance? (Part 1)

shane wescott — Fri, 24 Sep 2010 12:57:16 GMT

Interesting Guys.

First up, Yes I do work for AppSense

Second up, Yes performance on Windows systems and especially Shared Infrastructure (Citrix/TS/VDI/Virtual Servers etc) has been a large part of my gig for the last 6 1/2 years.

Our Performance Manager product improves scalability, and provides more consistent performance in any VDI environment.

That's not our corporate message, it's a message my customers give me (so I'm happy to use it).

I've given up arguing with Virtual Infrastructure "experts" about why our product won't help, or won't work due to cpu cycle splitting or some other hypervisor hocus pocus.

I just get customers to test it, they say it works, I'm happy :-)

So trimming down what a VDI OS has to do in the background improves performance - seems pretty logical to me.

Just as logical as granualr management of CPU and Memory INSIDE a VDI Guest with mean the guest gives more consistent performance, and uses less resources from the Host.

You learn something new everyday in IT :-)

re: Does OS "tuning" help VDI performance? (Part 1)

edgeseeker — Thu, 23 Sep 2010 21:04:48 GMT

Good job, Ron.

CPU utilization management inside each VM might also be a good idea to further improve perceived performance. Although the hypervisor can manage CPU utlization at the VM level, there's nothing to prevent runaway processes from pegging a particular VM. I'm actually surprised none of the VDI vendors have done this so far, especially since most of them have had a CPU utilization management offering for RDS for quite a while.

I didn't expect any improvements in terms of number of VMs per host. I've already performed a similar exercise by building a minimum-size desktop image using one of several guidelines and deployment kits out there.

I still like what Atlantis Computing does in terms of I/O acceleration. It's a night-and-day difference.

re: Does OS "tuning" help VDI performance? (Part 1)

gensem — Thu, 23 Sep 2010 18:34:47 GMT

Im with Feller on that.

Even if the performance doesnt change alot on chart (wich is somehow supicious to me). Making the UI lighter will make the protocol (ICA) life easier and "faster" in the end. Im not against eye candy but cpu cycles and bandwidth arent free.

Im yet to change my mind about optimizations, stop doing and using adm files for XD and XA. I think everyone should do it, because in the worst case scenario (if im completely misleaded) you get to know the products and the OS better.

re: Does OS "tuning" help VDI performance? (Part 1)

Daniel Feller — Wed, 22 Sep 2010 23:17:14 GMT

The results are interesting to say the least. Honestly, I would be happy if tuning didn't matter as it would make our jobs easier (but don't tell anyone as this stuff makes us look smart).

I know of a lot of the tuning tips are carry overs from the Terminal Services/XenApp optimizations and many of those do show improvements, especially when we get to memory management (w2k and w2k3). We used to also recommend to disable all of the splash screens and animations as the protocols couldn't handle it. So this begs the bigger question... Has technology improved to a point that makes these optimizations pointless? We know that ICA/HDX can do graphics much better than years ago, same for animations. We know W2k8/W7 is much better at memory mgmt than W2k3/XP.

I guess i would need to see more cases to see if it did indeed make a difference. As your test was only 1 VM, I'm hesitant to say "Get lost optimizations". As it doesn't appear that these settings hurt, I'm erring on the side of caution and plan to continue down the path of an optimized OS.

re: Does OS "tuning" help VDI performance? (Part 1)

Kimmo Jernstrom — Wed, 22 Sep 2010 18:06:32 GMT

Gahwd, OS tuning have for me been somewhat of an obsession and agony over the years from DOS to Windows 7/2008 R2.

Say, a lot of us surely remember Rich Dehlinger et.al MetaFrame Tuning Tips from late ‘90s to early ‘00s. See here for example - www.thin-world.com/.../MFTips1.pdf and others.

Tuning ADM templates, batch files and countless tools flew high and low. An example of my own idea of the bare basic “standard” tuning from Windows 2003 TS era is recorded here - jernstrom.org/.../Standard5.zip.

Countless other documents, tools, scripts, adm templates, posts etc. are living in dropbox, discarded USB-pins, dead computers and whatnot. I never disabled any services oddly enough.

It’s not like I’ve not been challenged to those tuning things as I guess no one of us have. My explanation, excuse if you wish, was that these were suggestions and examples that might make some impact and should at least be considered for whatever value they might have. Sometimes some stuff did really matter, other times maybe not so much, still way overdone by any measurement.

The challenge is of course – Is it really worth it? I don’t know, I’m a recovering obsessive tuner :)

As some, I skipped the Vista/2008 stuff (except for GPO Preferences) and jumped back with Windows 7 and 2008 R2.

As @Helge might recall I went nuts with the 7/08R2 shell, meaning Known Folders and specifically Libraries, aka iShellFolder interface (Wndows 7 SDK shlib.exe build) and the RemoveDuplicateProfileLinks.exe source from The Deployment Guys blog.

As of now I’m still as much ambivalent as ever before, just a bit more pragmatic. Leaving it bee, for surely I’m not the one to administer and maintain? :)

I guess I agree with many that best is to just tune the obvious matters in the OS by requirement and concentrate on the application tuning and standard streamlined Workspace environment.

For all I know VM sprawl, wasted disk and problematic disk IOPS are the real problems as of now, way before CPU and Memory allotments.

re: Does OS "tuning" help VDI performance? (Part 1)

Ron Oglesby — Wed, 22 Sep 2010 17:17:38 GMT

Looking at the VMware metrics Active Memory and Granted Memory.

re: Does OS "tuning" help VDI performance? (Part 1)

Tim Mangan — Wed, 22 Sep 2010 16:39:28 GMT

Ron -

Just what memory measurement is that? I am guessing that after tuning, the OS had lower committed memory and thus was less agressive in paging things out of RAM, possibly leading to the higher memory measurement. If so, this is a good thing which will show up as an added bennefit in multi-VM tests.

re: Does OS "tuning" help VDI performance? (Part 1)

Ron Oglesby — Wed, 22 Sep 2010 14:38:15 GMT

Robert and Dan,

The tweaks listed had no impact (or none that could be measured). Most the these services and changes do so little (as shown by the limited memory and CPU help) that I saw no difference in IO. Both VMs were essentially the same from the number of operations and amount of data written or read.

I think Dan's tweak on last access time stamp may show some improvement. But my next one (part two) will talk some about that.

My interesting finding (in futher tests) is the serious difference in IO for logon storms based on various profile configurations. Unlike Reboot storms, logon cant be staged or scheduled. Reboots can be mitigated at least by scheduling them somewhat when you update VMs.

Logons... not so much. 8am call center workers all login 7:59 - 8:01 (or whatever).

I found that local profiles reduced IO per desktp by more than 2/3rds vs a standard romaing profile.

A standard roaming profile, w/ folder redir for Windows7 (on a desktops that is used) is generating an average of 1600+ IO over a 60 second logon period while a stadard profile (same profile but local) shows about 500 over the 60 second period. It makes sense, but it is often just assumed that you must have a romaing profile. Here is a reason to think about.

Robert,

Know you are in the IO business, and with an IO accelerator the profile thing isnt so important. The only benefit of going local vs roaming in that case is to speed up login.

re: Does OS "tuning" help VDI performance? (Part 1)

robertkadish — Wed, 22 Sep 2010 14:16:27 GMT

Dan brings up a question I have. I think it will be interesting to see what the impact on IOPS is with these tweaks.