we've got 2 x HP DL360 G5s with Quad Quad Xeons 2.6GHz and 32GB of memory each running XenServer 5.5 and they access an OpenFiler box (with 8 x 320GB SAS 10K drives) via copper CAT5 (1GB) for the storage.
We've used this setup for testing a lot of stuff which has worked out perfectly, but now we are moving to use this setup in production and are experiencing performance issues. There are currently 27 VMs split across the two servers which are all in use (albeit not doing a lot of work) but they seem "slow", especially our employee thin clients - they always complain logging in times and accessing files via the network are slow.
Personally, I think it's a throughput issue and we should go SCSI or FC for our storage but I need some evidence to back my theory up and I'm quite new to Xen (it was setup by a previous employee).
My questions: from the info I've gave would it be possible that the storage box is overloaded, trying to squeeze too much over that one cable;? how do I monitor network access in real-time from the XenServers themselves?