Hi,
We have a new Citrix farm based on XenApp 5.0 on Windows server 2003 R2 (+SP2).
Our supplier setup it up next to our old MetaframeXP farm with new hardware and the use of PVS and the XenApp servers are all VMWare machines. We also use RES Powerfuse.
Recently we moved our users from the old farm to the new farm and as the number of users grew they were experiencing sudden freezes of their programs. The more users are logged on to a new server the time between freezes gets shorter. Freezes happen at random intervals and last for about 2 to 20 seconds.
We installed the latest version of all Citrix, RES and Windows software to exclude any existing known fixes but the problem is still there.
Further investigation shows that only those applications freeze that are activly using a network share or UNC path (listing a directory or reading a file for example). Other programs which communicate over the network not using a network share do not freeze (SQL query to a SQLserver or a simple ping/pong program or RDP of ICA screen updates).
When i use Proces monitor and filter all lines starting with \\ I scrolls until the freeze happens and cotinues to scroll after the freeze.
I created a little DOS batch script, to detect the freeze, which reads from a file on a network share in a loop and does some echoing to the screen. It pulls the CPU high and it shows the freeze moment because the CPU usage of the progam drops to 0. For the script see attachment test_freeze.cmd.
Following situations have been tested:
1. XenApp server with one script reading from external server (\\server1\e$\dinsdag.txt) -> Random freezes.
2. XenApp server with two scripts active. One reading from server1 (\\server1\e$\dinsdag.txt) and second reading from server2 (\\server2\e$\dinsdag.txt). -> Both scripts freeze at the same time. Freeze moment is Random.
3. XenApp server with two scripts active. One reading from server1 (\\server1\e$\dinsdag.txt) and second reading from local partition (D:\dinsdag1.txt). -> Only script which reads from server1 freezes other scripts continues.
4. XenApp server with two scripts active. One reading from server1 (\\server1\e$\dinsdag.txt) and second reading from localhost with UNC path (\\localhost\d$\dinsdag.txt same file as situation 3). -> Both scripts freeze at the same time. Freeze moment is Random.
5. XenApp server with one script active and a standalone Vista computer with on scripts active. XenApp server reading from server1 (\\server1\e$\dinsdag.txt) and Vista machine reading from (\\XenAppserver\d$\dinsdag.txt same file as situation 3) -> Script on XenApp server freezes but script on Vista computer continues and never freezes.
The freezes also appear when only one user is logged on to the machines through RDP or Console.
Another XenApp server on the same VM host also has these freezes but not at the same times as the other. They do use the same network hardware (connected to same virtual switch).
Extra info about the setup:
VPS server is a virtual machine. vDisks are stored on a SAN. Version 5.1 With SP2.
We have 10 XenApp servers all using the same vDisk as their boot disk (C-Drive). All XenApp servers have a second local disk (virtual VMware disk) on which the pagefile is stored. vDisk is in Standard Image mode and Cache on devices HD's.
Any help is appreciated.
Regards,
Michel Verbraak.
We have a new Citrix farm based on XenApp 5.0 on Windows server 2003 R2 (+SP2).
Our supplier setup it up next to our old MetaframeXP farm with new hardware and the use of PVS and the XenApp servers are all VMWare machines. We also use RES Powerfuse.
Recently we moved our users from the old farm to the new farm and as the number of users grew they were experiencing sudden freezes of their programs. The more users are logged on to a new server the time between freezes gets shorter. Freezes happen at random intervals and last for about 2 to 20 seconds.
We installed the latest version of all Citrix, RES and Windows software to exclude any existing known fixes but the problem is still there.
Further investigation shows that only those applications freeze that are activly using a network share or UNC path (listing a directory or reading a file for example). Other programs which communicate over the network not using a network share do not freeze (SQL query to a SQLserver or a simple ping/pong program or RDP of ICA screen updates).
When i use Proces monitor and filter all lines starting with \\ I scrolls until the freeze happens and cotinues to scroll after the freeze.
I created a little DOS batch script, to detect the freeze, which reads from a file on a network share in a loop and does some echoing to the screen. It pulls the CPU high and it shows the freeze moment because the CPU usage of the progam drops to 0. For the script see attachment test_freeze.cmd.
Following situations have been tested:
1. XenApp server with one script reading from external server (\\server1\e$\dinsdag.txt) -> Random freezes.
2. XenApp server with two scripts active. One reading from server1 (\\server1\e$\dinsdag.txt) and second reading from server2 (\\server2\e$\dinsdag.txt). -> Both scripts freeze at the same time. Freeze moment is Random.
3. XenApp server with two scripts active. One reading from server1 (\\server1\e$\dinsdag.txt) and second reading from local partition (D:\dinsdag1.txt). -> Only script which reads from server1 freezes other scripts continues.
4. XenApp server with two scripts active. One reading from server1 (\\server1\e$\dinsdag.txt) and second reading from localhost with UNC path (\\localhost\d$\dinsdag.txt same file as situation 3). -> Both scripts freeze at the same time. Freeze moment is Random.
5. XenApp server with one script active and a standalone Vista computer with on scripts active. XenApp server reading from server1 (\\server1\e$\dinsdag.txt) and Vista machine reading from (\\XenAppserver\d$\dinsdag.txt same file as situation 3) -> Script on XenApp server freezes but script on Vista computer continues and never freezes.
The freezes also appear when only one user is logged on to the machines through RDP or Console.
Another XenApp server on the same VM host also has these freezes but not at the same times as the other. They do use the same network hardware (connected to same virtual switch).
Extra info about the setup:
VPS server is a virtual machine. vDisks are stored on a SAN. Version 5.1 With SP2.
We have 10 XenApp servers all using the same vDisk as their boot disk (C-Drive). All XenApp servers have a second local disk (virtual VMware disk) on which the pagefile is stored. vDisk is in Standard Image mode and Cache on devices HD's.
Any help is appreciated.
Regards,
Michel Verbraak.
