We are running a Dell PowerEdge T710 with a PERC H200 RAID controller and two mirrored SAS drives.

We just patched to Update 2 because our SAS drives were extremely slow and it mentioned somewhere straight 4.0 esxi didn't support our controller. Anyways, after installing I ran CyrstalDiskMark 3.0 x64 benchmarking on a WinServer 2008 VM with nothing else running on the machine. I was getting faster numbers than my local dev computer's 10,000rpm raptor drive but the times still seem a bit off.

less than 10 rep so can't post images or > 1 link apparently

server on left, raptor drive on right

Any advice on how to speed this up or anything I could be doing wrong? The read speeds are probably about write but writing is slow, the problem is I really don't know what sort of numbers I should be expecting.



Perhaps this is the problem of the controller: http://communities.vmware.com/message/1572066

  • yeah, we have no write caching on our raid controller – nextgenneo Oct 11 '10 at 18:47

Most likely cause, given that you're measuring from within a VM, is that you did not install the VMware tools in your guest OS. You can do this using the vSphere Client.

  • nah, it's installed and patched to the latest – nextgenneo Oct 11 '10 at 17:32

Slow write speeds are usually bad/disabled cache. Have you checked if your raid controller has this enabled (and that there are no battery faults)?

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