what CPUs? I had a similar issue with W2K3 x64 and the AMD Opteron - was a boot.ini flag that cured it. Not sure is w2k8 has a similar issue/cure esp. since it uses BCD On Thu, Jan 6, 2011 at 4:10 PM, Andy Friar <Andy.Friar@xxxxxxxxxxx> wrote: > I’m have a problem with the following Windows 2008 SP2 Enterprise x64 > > XenApp 5 Enterprise R01 > > > > Boxes are Dell blade 8 core + HT 49Gb RAM > > Local manadatory profiles with full Appsense suite utilising EM + > Personalisation service. > > Desktop / My Documents / Favourites redirected to a Netapp Filer running > CIFS. > > > > The more users that come onto the box the slower the machine gets. > > > > @ 0-45 users the box is responsive, logon times are good but it still has > this apparent lag when accessing local apps > > @ 50 the lag is getting worse sometimes freezes but always comes back. > > @ 60 logon times are substantial, just selecting a cell in excel can take > 30+ seconds. > > > > Performance counters seem fine > > > > 14% processor time > > 25k context switches / sec no massive jumps > > 0 Processor queue length > > 99% disk idle > > 0 disk queue length > > 15-20k threads > > 0 Redirector\Current Commands > > > > The only large one is system calls / sec which can be anywhere from 80k to > 1.5m, I’ve cut down the apps but system calls are still high. > > > > To me the server feels as if it has no cpu left, but given the resources > free it looks more like an i/o problem, I’ve tuned the smb with the > following > > > > > [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Lanmanserver\Parameters] > > "MaxWorkItems"=dword:00002000 > > "MaxMpxCt"=dword:00000800 (subsequently has > been changed to match the Netapp) > > "MaxRawWorkItems"=dword:00000200 > > "MaxFreeConnections"=dword:00000064 > > "MinFreeConnections"=dword:00000020 > > > > > [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Lanmanworkstation\Parameters] > > "MaxCmds"=dword:00000800 > > > > [HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session > Manager\Configuration Manager] > > "RegistryLazyFlushInterval"=dword:0000003C > > > > > > The NetApp filer has had cifs.max_mpx set to 1124 so I’ve subsequently > changed the citrix servers to match this number rather than the 2048 > previously. > > It’s running around 30%cpu 2000 io/sec 98% cache hit. > > > > Any suggestions on where else I might look into what is causing the > bottleneck? > > > > Thanks > > > > Andy > > >