Following problem is bothering me for some weeks now.
Terminalserver (TS) W2K3 64bit, XenApp 5 rollup 6, most current HW (HP blade 460cG7, 2 sockets, 6 cores each, 192 GB => restricted to 6 cores in BIOS, restricted to ~32GB by Windows bootloader /MAXMEM=32000). Attached to a SAN solution (Fiber channel) and Gigabit.
Application mix mostly Office 2003 / Acrobat reader / IE 8 / etc. User profiles & user data stored on a Windows 2008R2 fileserver. Users work with active and open PST files on the fileserver (FS). Some have more than one PST opened in parallel. Size up to several GB.
TS & FS tuned following KB324446 and http://blogs.citrix.com/2010/10/21/smb-tuning-for-xenapp-and-file-servers-on-windows-server-2008/
BIOS is up2date, BIOS settings are according to guidelines for "low latency applications". Xenapp CPU management is active.
Same FS is accessed by all servers in this silo. As long as load is spread to enough TS, each below ~60 sessions, each individual TS works fine. Pushing server up to 75-80 sessions, with still some free resources (CPU, memory) remaining, the server gets unusable. As soon as nb. of sessions drops below 60, again, things are fine again.
Users experience "sluggish" server, with "bad" performance (key strokes come delayed etc.). No data loss.
Observation is that the TS starts to freeze intermittently for 1-10 sec. Obviously all user sessions are affected at the same time. This is reproducible on any servers in the same silo, most of them virtualized, one (HW described above) running without hypervisor to exclude ESX as the culprit.
Perfmon shows gaps in its graphs when freeze happens. Edgesight (only basic version) delivers no clue.
Already having looked at the obvious, eventlog shows nothing specific, but honestly I'm stuck now.
Work assumption for the time being: a Windows resource gets exhausted. Until it becomes available again, all requests are queued and processed afterwards.
What should be monitored? By which tool?
Which settings to be checked?
Any other idea?
Thx. in adv.