Webcast: Citrix and Terminal Server Performance Tuning (Now with Q&A)

I gave a live webcast about Citrix MetaFrame and Terminal Server performance tuning and optimization. This webcast is the audio companion to my Terminal Server performance tuning white paper , so be sure to download that paper if you have not done so already.

I gave a live webcast about Citrix MetaFrame and Terminal Server performance tuning and optimization. This webcast is the audio companion to my Terminal Server performance tuning white paper , so be sure to download that paper if you have not done so already.

This webcast was hosted by Jupiter Media and sponsored by RTO Software. It has been archived, so you can listen to it anytime.

Live Q&A from the Webcast

There was a Q&A session at the end of the webcast. Unfortunately, we could only answer some of the questions during the event, so I'm providing the rest of the answers here. I've edited the questions for grammar and spelling, and similar questions have been combined.

I tried to answer every single question that was posted. However, some of the questions just didn't make sense. If you asked a question that's not answered here, you probably need to clarify your question. You can send your clarification directly to me at brian@brianmadden.com. Also, some of the questions were geared towards Bernd. I sent him those questions Tuesday morning, so I'll post his answers when I get them.

Q: How do you explain the statement that Windows 2003 server can handle about 20% to 80% more users than Windows 2000?

A: First of all, let me qualify that statement. Windows Server 2003 can support many more users than Windows Server 2000 in Terminal Server scenarios in non-resource constrained environments. As to “why” this is the case, I think it has to do with a lot of the architectural changes that Microsoft introduced in Windows Server 2003.

Q: What about slow logout?

A: Tracking slow logouts is done in the exact same way that you would track a slow logon. You can track slow logouts with by enabling logging on the userenv.dll just like you can track slow logons. You also need to make sure that you're aware of everything that happens at logout. (Logout scripts, roaming profile copying, etc.)

Q: How many more users will Windows Server 2003 support?

A: Standard caveats apply here, (varies by CPU, users, applications, etc.) but a safe bet is 10 - 30% more users.

Q: I have a 2003 environment and use primarily Wyse terminals. Do you have any experience with Wyse Expedian?

A: Wyse Expedian is an OEM version of RTO TScale. i.e. The two products are the same thing with different logos, so use whichever one makes you happy.

Q: Are there many differences between Terminal Services in Windows 2000 and Windows 2003?

A: Yes. For the complete details, read my white paper about what's new in Terminal Services in Windows Server 2003, available at https://www.brianmadden.com/opinion/Terminal-Services-for-Windows-Server-2003

Q: You said that windows kernel memory cannot support more than 200 users. How to increase it?

A: Yes, I mentioned that due to the architecture of Windows 2000's kernel memory, you'll never get more than about 200 users on a Windows 2000-based Terminal Server. (This does not apply to Windows Server 2003.)

You cannot change this explicitly, although you can tweak it a bit in certain situations. This is explained fully in my white paper.

Q: Do most of these hotfixes require a phone call to download from MS? In other words, are they hotfixes in addition to those in windowsupdate.microsoft.com?

A: This question is referring to the statement I made about most pauses, spikes, and hangs being fixed by hotfixes or firmware updates. The answer is “yes.” Most of these hotfixes can only be obtained by calling Microsoft.

Q: What's your opinion of Softricity's SoftGrid ?

A: I like SoftGrid a lot. Softricity released a new version of their product late last year (which I wrote about last November). While it's an expensive product, it's the only way to go if you have hundreds or even thousands of applications you'd like to bring into your Terminal Server or MetaFrame environment.

Q: What about server location? We would like to centralize and consolidate servers in the Western US, but they need to be accessible from Asia/Pac and Europe without the latency issues. What's the best way to approach this as we plan our farm rebuild?

A: I talk a great deal about server location in all of my books. Lucky for you, the chapter from my Citrix book where that is covered is available as a free download.

Q: Can Terminal Services manage printers correctly with remote users?

A: It's hard to answer this question without knowing exactly what you mean. I have posted the Printing chapter from Ron Oglesby and my new book “Terminal Services for Microsoft Windows Server 2003, Advanced Technical Design Guide.” You can view or download that chapter here.

Q: Users inside the Firewall work well but users outside the firewall get random disconnected after a few minutes of connection time.

A: If your issue is random disconnects, then it's probably safe to assume that a lack of bandwidth is causing your problem. There are a few things you can try. First, you might want to verify your ICA Keep Alives setting in the registry of your MetaFrame servers. (If you're using MetaFrame.) Second, you might try hardware quality of service device, like those from Allot, Packeteer, or Sitara. Finally, if you really want to dig into your problem, you can check out a tool like Ozona's ICA packet sniffer.

Q: How can you know if need Citrix or can use Terminal Server?

A: I wrote an article a few months ago that compares MetaFrame XP, Terminal Services on Windows 2003, New Moon Canaveral iQ, Jetro CockpIT, and DAT Panther. The article is available here.

Q: We experience excessive processor queue lengths ( average 2-6 per processor) while Total Processor Utilization is only 30-50%. We've confirmed that we don't have excessive hardware interrupts. Can you think of any other directions we should research to further understand what is truly limiting our server performance? We've read you white paper – Thanks.

A: So what you're saying is that I can't say “just read the paper” for this answer? :-)

Q: Is the ICA protocol limited to 20kbps at the upper end or are there mitigating factors that can affect the maximum bandwidth used? What effect does a WebEx client have on the bandwidth utilized over Citrix?

A: There is no upper limit to the amount of bandwidth an ICA client can use. Remember, ICA can support resolutions of 32,000 x 32,000 at 24-bit color with full audio. I would think those sessions would use a bit more than 20kbps. Seriously though, audio quality, printing, port mapping—all of that directly affects the amount of bandwidth an ICA session uses.

As for WebEx, I've never used it from within an ICA session, so I cannot comment directly on bandwidth usage. I would image that it wouldn't affect things too much, though.

Q: For Brian Madden: We have a Citrix MetaFrame XPe FR 3 farm consisting of 5 servers in one zone. We currently publish apps\file access to WinNT, IBM & Netware. We are suddenly running out of licenses for Netware, finding that each Citrix session launched by the same user, who is already authenticated to Netware Svrs, is being requested to logon to Netware for each additional application - causing our licensing issue for Netware. Is there a script or policy that can be setup to only request Netware logon/authentication for the first application launched?

A: I have no idea, and I actually haven't touched Novell in over a year. I would suggest posting this question to the THIN list. I'm sure you'll get a response there.

Q: Should we REALLY turn off Hyperthreading on our Windows 2000 farm?

A: Yes.

Q: I have heard that there are problems with installing SP4 on servers with MF SP3, why is that?

A: I have no idea. You'd have to ask Citrix and/or Microsoft. I asked Citrix last October, and here's what they said.

Q: Any certain “cons” to upgrading a Windows 2000 Server to Windows 2003?

A: Probably the biggest “con” in my mind relates to licensing. Windows XP Professional licenses include a “free” Terminal Server CAL for Windows 2000. However, the “free” CAL for Terminal Services running on Windows Server 2003 only applies to copies of Windows XP purchased prior to April 25, 2003. Therefore, upgrading your Terminal Servers from Windows 2000 to Windows 2003 could potentially be quite costly.

Q: I have experienced problems with printer queues hanging with Microsoft Office apps. Do you have any suggestions?

A: This question is fairly broad. I would suggest being more specific and emailing your question to the THIN list.

Q: How many Windows 98 computers can connect to Citrix MetaFrame XP with Windows 2000 Server (without purchasing extra licenses)??

A: None. They would all need Window 2000 Terminal Server Client Access Licenses and MetaFrame XP connection licenses.

Q: Have you guys heard of any problems with optimization with TS in a Novell environment (Windows 2003 server running Novell client 4.9 SP1)

A: I don't know of any Terminal Server optimization problems that are specific to Novell environments.

Q: How can we optimize the printing over the Users printers using Terminal Services?

A: Printing optimization in pure Terminal Server environments usually comes from using one of four popular third-party tools from either ThinPrint, triCerat, EOL, or Uniprint.

Q: When will Microsoft add the ability to save a RDP session to a file? Later, after reboot, it can be reloaded?

A: What you're referring to is called “session hibernation.” This is similar to how laptops can hibernate and shut down, and then be restarted right where they left off. This is on several peoples' “wish lists” for Terminal Server features, but I don't know when (or if) it will ever become a real feature.

Q: When adding a new server to an existing Citrix farm - all the hotfixes applied to the existing servers in this farm - do these need to be applied to the new server being added to the farm?

A: If it were me, I would do everything I could to ensure that all Citrix servers are identical in terms of hotfixes.

Q: ctfmon.exe continues to hold Citrix users' sessions open long after they have successfully logged off. Each new service pack applied to the Citrix servers for Office XP places this file back in use after manually removing it. Is there anyway to prevent this from occurring with each new Microsoft Office service pack?

A: I don't know of anything off the top of my head. Other than Googling for an answer, I'd send an email to the THIN list to see what other peoples' experiences are.


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This message was originally posted by Me on March 17, 2004
Will this be downloadable for offline viewing. I will be in bed at that time, and i dont want to miss this.
This message was originally posted by Brian Madden on March 23, 2004
In Terminal Server environments running on Windows 2000, having hyperthreading enabled hurts performance. In Terminal Server environments running on Windows 2003, enabling hyperthreading helps performance. For more information, check out this paper that Tim Mangan wrote: www.tmurgent.com/images/WP_HyperThread.pdf
This message was originally posted by Mkeen on March 23, 2004
you mentioned in the web forum Q&A to turn off hyperthreading. Why?
This message was originally posted by an anonymous visitor on May 4, 2004
Hyperthreading on first generation Intel Procs can only hurt performance on single threaded type apps, which MetaFrame is not. It has nothing to do with the OS. P4 chips > 2.4GHz doesn't hurt performance. H/T gives a 10-15% boost in performance.

See Citrix written article "How Adding Processors and Enabling Hyper-Threading Affect User Capacity of MetaFrame Servers" at www.dell.com/citrix
This message was originally posted by Brian Madden on May 5, 2004
So now we have two papers, one written by Citrix (on dell.com) and one written by an independent tester (on tmurgent.com). Which one is correct? It's up to each reader to decide. The bottom line is that you'd better test your own environment. If you have a Windows 2000 Terminal Server that's been running HyperThreading since day one, you might want to try disabling it to see what happens. I can say for a fact that I've seen environments where disabling HyperThreading on W2K has increased the Terminal Server performance. Then again, the paper from Citrix Engineering on dell.com claims otherwise. My only advice? Try them both and see what the case is in your environment.
This message was originally posted by David Caddick on May 17, 2004
Hi Brian,
You mention Ozona's ICA packet sniffer in this article and I'd like to find out more about this, but I'm obviously not looking in the right place on the web. Could you let me know any more details?
Thanks in advance,
David Caddick
This message was originally posted by Gabe Knuth on May 21, 2004
www.ozona.es will get you to their site. Better get some babelfish going.
How to increase the print spooler size in a Windows 2003 Terminal Server?