Citrix on ESX 4 U1 - Slow login times

[thomps01]

I'm sure they'd be just as slow if not slower using ESX 3 but I'm looking for some assistance.

On a physical Citrix server, logins are 1 - 4 seconds.

The virtual - 16 - 23 seconds.

I'm looking for performance enhancements that I can make to me VMs to try and reduce the login wait times.

The hardware is fine (HP BL685 (24 cores, 64GB RAM). And there's nothing pushing it yet.

Network 10Gb

I'm planning to test the configuration with VMXNET3 tomorrow, but does anyone have a list a best practices I can use when testing?

[TomHowarth]

As the other poster mentioned, look at the VM's performance before, during and after one of these

slow logins via the VIClient can you see where it's running 'hot'

(i.e.CPU, CPUREADY, memory, network, disk etc.),

Alternatively monitor it via ESXTOP. also remember to check context switched in the guest to see if the VM is waiting for CPU time.

these will give you good insite into where the performance issue is.

Remember that just because the vkernel now utilised opportunisitic locking on multi-threaded guest, it does not mean that you can over load your host too much. Logons is one of those processes that are truely multi-threaded, therefore all CPU's in the guest will be utilised fully. So what can give acceptable performance duing the normal day activities can crawl to a halt during logon and logoff.

furhter remember that procmon is your friend. monitor you guest with it for time outs etc

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Tom Howarth VCP / vExpert

VMware Communities User Moderator

Blog: www.planetvm.net

Contributing author on "[VMware vSphere and Virtual Infrastructure Security: Securing ESX and the Virtual Environment|http://www.amazon.co.uk/VMware-VSphere-Virtual-Infrastructure-Security/dp/0137158009/ref=sr_1_1?ie=UTF8&s=books&qid=1256146240&sr=1-1]”.

[AnatolyVilchins]

See content here - http://serverfault.com/questions/113009/citrix-on-esx-4-u1-slow-login-times.

Message was edited by: Dave.Mishchen…

[TomHowarth]

once again I am in agreement about the disk alignment, there are still too many variables not know to be able to give you a decent answer. Disk alignment is one issue but also what is the Raid set that your VMDKs are running against, for example a RAID 5 disk set will require 4 writes to every phyiscal write request and as a logon is all write requests this can put in a significant delay

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Tom Howarth VCP / vExpert

VMware Communities User Moderator

Blog: www.planetvm.net

Contributing author on "[VMware vSphere and Virtual Infrastructure Security: Securing ESX and the Virtual Environment|http://www.amazon.co.uk/VMware-VSphere-Virtual-Infrastructure-Security/dp/0137158009/ref=sr_1_1?ie=UTF8&s=books&qid=1256146240&sr=1-1]”.

[peterhigsonuk]

Actually, as he's using Citrix, it'll be a synchronous process for GPO processing, and if he has significant GPOs processed, this will be happening on a single thread timeline.

http://msdn.microsoft.com/en-us/library/aa374350%28VS.85%29.aspx

this could be a limiting factor, I have the same issue, and this seems to be down to latency incurred processing synchronously alongside wire transfers of small packets (again, a characteristic of GPO processing)

worth some research here into what component of your login is actually the slowest bit

here's a starting point :

http://support.microsoft.com/kb/221833