3 Replies Latest reply on Jun 22, 2012 12:51 PM by greedj1

    Bad performance (huge write latency) on PERC H200 (DELL - mptsas)

    florent42 Lurker



      I have two servers. One DELL R510 with PERC6/i (megaraid_sas driver), and one DELL R210 with PERC H200 (mptsas driver). They're both configured as RAID1 (mirroring).


      On the R510, guests have great performance. ESXi reports a datastore write latency between 0 and 2ms. Wonderful.


      However, on the R210, guests are incredibly slow, due to I/O waiting. "top" shows 20% of "wa" (I/O wait), and guest load is usually around 0.20 (while doing nothing!). Maximum write speed is around 6 Mb / s. Not really usable.


      ESXi reports datastore write latency between 200ms and 500ms. That explains bad guests performance. Is this a known issue with this hardware ?

      RAID status is "OPTIMAL", so the latency does not come from a recovery.


      What can I do ? Are there some hidden configurations or actions that could be done via ssh or through the vSphere Client to get decent performance ?


      Thanks for your help.





      Message was edited by: florent42 - added OPTIMAL state