Xenserver 5.5 slow to copy large files

[pinkpanther56]

We have a Xenserver hosting several Windows VM’s connected to an iSCSI SAN via 3x 1Gb NICs that are in an LACP bond. During normal load the setup performs fine the two virtual file servers serve files to 400 clients all day long without issue, these files are mainly word, excel and jpeg’s. The DC and print server also on the same Xenserver perform fine as well.

The problem comes when trying to copy large files I tried to export a 10 Gb VHD from Xencenter the other day and it took over an hour, I also see slow times when copying large files to the Windows VM’s the copy starts very fast but then drops off to very slow speeds. The server running Xencenter is a physical HP box that I use for backups and is a quad core with a Gb NIC so I don’t think that’s the problem.

I’ve been told by Citrix that Xenserver doesn’t support jumbo frames which is a shame as the SAN does so that’s not something I can set. The SAN and Xenserver are connected via a HP ProCurve 2910al switch which again should be more than enough to cope with the load.

The Xenservers are on Sun x4150s servers running Xenserver 5.5.

Can anyone suggest where I should start looking to troubleshoot this issue?

If you require more information please ask.

Thanks.

 

[Davetoo]

Without delving in too far, did you apply the latest update to Xen?

I'm Certifiable, not cert-ified.
It just means my answers are from experience, not a book.

There are no more PDC's! There are DC's with FSMO roles!

 

[pinkpanther56]

I haven't applied Update 2 yet, is there specifically a fix for this issue in there?
I'll take a peep.

 

[Davetoo]

Not that I'm aware of, however, given the nature of XenServer it's best to have the latest updates applied and verify the issue still exists before anything else.

I'm Certifiable, not cert-ified.
It just means my answers are from experience, not a book.

There are no more PDC's! There are DC's with FSMO roles!

 

[pinkpanther56]

I'll have to wait a while to apply that update.


One thing that i've noticed is that Jumbo Frames are enabled on the SAN iSCSI link but Xenserver 5.5 doesn't support Jumbo Frames.

Could this have an affect on performance?


This sounds similar.

http://forums.citrix.com/message.jspa?messageID=1385662

Thanks.