Monday, May 9, 2011

Citrix XenApp 6.0 Servers Freezing

When we finally made our way through our XenApp 5.0 farm freezes, I never thought that I would revisit such a problem so quickly.  When we made our upgrade to XenApp 6.0 and Windows Server 2008 R2 I thought for sure we would be jumping into a much more stable environment.  Unfortunately, I was wrong.

Shortly after making the upgrade we noticed that our Citrix servers became unresponsive at random times throughout the day: you could ping them, but that's about it.  Any attempt to RDP or log in even at the console level was an absolute failure.  If you are experiencing this problem, I would recommend upgrading your servers to Server 2008 R2 SP1, and applying the following Microsoft Hotfix: KB 2465772.  In addition, you're going to want to install at LEAST this Citrix Hotix as well: CTX127023.  But really, I would install as many Public Hotfixes for XenApp 6.0 as possible that apply to your environment.

If that would have been the end of the freezing saga, I would have been content.  However, the freezing dragon decided to rear its ugly head again: whenever we tried to shut down a Citrix server after having a decent amount of load on it, it froze.  Basically, it would sit on the Windows "Shutting down..." screen with the spinning circle to never fully shut down or recover without a hard power off.

After working with Microsoft and Citrix, it turns out that there is a Citrix Hotfix that's working its way toward becoming public (supported by Citrix), that should be available in the coming weeks.  If you are experiencing this same issue (freezing when shutting down) you're going to want to keep your eye out for Hotfix 46 (full name: XA600W2K8R2X64046).

UPDATE: I've added a new post that provides links to this hotfix.

In the meantime, there are a couple pages you should be keeping an eye on:
  1. The list of Public Hotfixes currently available for XenApp 6.0
  2. A list of recommended Microsoft Citrix Hotfixes for XenApp 6.0 and Server 2008 R2
Both of these get updated from time to time, so you'll want to bookmark them and see what's new whenever you get a chance.

As always, this is what worked for me, in our environment, so your mileage may vary and I won't be responsible for any problems this post may cause :)


Anonymous said...

Thank you for this post.
The infos is extremely valuabl.


Matt Augustine said...

No problem -- thanks for reading, and for the encouragement!

Labmouse said...

Yep, this all sounds very familiar! Even with SP1, that MS Hotfix and all the public XenApp 6 hotfixes, we still get servers getting unresponsive and needing a reset. Its much better than before though - XenApp 6 unpatched is really quite unstable.

XenApp patch 046 is available now by the way - we're assured by Citrix it will fix the Shutting Down issue - but then they did say that about 018...


Matt Augustine said...

LM, I totally agree! Unpatched, this whole environment was unstable and unusable! So far it seems like 46 has helped at least with the reboots as our patched servers rebooted OK this weekend... but time will tell! Thanks for stopping by and commenting.

DiKoTa said...

Hi Matt,
I am also using XenApp and I been having a nightmare. Sometimes during the day,my servers will freeze with users logged in.When that happens,users cannot log off and some cannot login. I will to have power off the virtual machine as the shutdown from vcenter will not even work. I sometimes power off my machines more than 3 times in a day.All my xenapp servers are virtualised in a vmware 4.1 environment. After reading your,I went on to install service pack 1 or Win R2 and upgraded servers will not take in users,had to uninstall the sp and then it worked fine but I am still left with the freezing issues. Will go ahead and install the hotfix but I wished I could do it over SP1. Any workaround after installing sp1 for servers to take in users?
Thanks for the post, nice one!1

Matt Augustine said...

Hi Moitshepi,

Yeah -- Citrix has been quite a nightmare for me off and on as well!

Regarding your specific SP1, I'm not entirely sure. It's possible that some Citrix or Microsoft hotfix may resolve the issue for you, but unfortunately, I don't have anything specific that I did.

Take a look at the following forum. Perhaps there's something in there that may help:

CitrixGuy said...

Good to hear I am not eh only one. You might also consider MAC users. They can affect the stability of a farm. MAC machine names should be alpha numeric only and the Citrix servers should have east Asian names enabled as well as reading rigth to left including Thai. I am looking for the specifica documentation that alks about this one and had not seen it pop up for a few years. We had done this on XenApp 4 and now looks like we need to do it for XenApp 6 and 5 as well.

Matt Augustine said...

Thanks for the tip CitrixGuy -- let me know what you discover.

Anonymous said...

The saga continues on 6.5 as well.

Dean Galloway said...

Thank you for this post. This revived my lab after running published apps just hung the Xenapp server..

I found it so hard to believe right off the DVD, Xenapp 6 just didn't work.