The domU in my environment is a xenserver 5.6 fp1 installed on a regular desktop with intel board and i3 processor. I have 8GB or RAM installed and 1 500GB SATA HDD. Obviously, i don't have RAID and i was wondering whether it would have an effect on the VM disk read/write speed if i increase the number of drives as local SR.
Is it just more storage i'd be gaining and zero effect on the VM disk speed?

1 Answer 1


It depends on what RAID level you use and your usage characteristics.

If you converted your single slow consumer drive setup into a RAID 0 array it's be faster yes but would introduce a very significant risk of complete array failure.

If you converted it to RAID 1 then you may see some performance increase dependent on load type but would make your system more resilient to failure.

If you converted it to RAID 5 that would be stupid.

If you converted it to RAID 6 that would be ok but you're see writes taking longer.

If you convert it to RAID 10 you'd see performance and resilience benefits all round.

This site's for professional sysadmins, did you not think to search previously asked questions? if you'd searched for 'raid' you'd have been linked to THIS previous question which might have been more help to you and less of a duplication of effort for us.

  • Chopper3, I dont have raid and i cant create any sort of array with the 2 drives combined, the idea was just whether it would improve the vm disk speed with 2 drives (no array whatsoever) as an SR instead of one if i add another drive and attach it as second SR
    – user128049
    Jul 12, 2012 at 10:21
  • Not a great question - ultimately we can only respond with "...it depends...", there's not enough information here.
    – Chopper3
    Jul 12, 2012 at 10:22
  • seems like you're not getting the point. This is NOT raid related for me to have poorly researched in the first place, i have many raid scenarios that i've helped discuss in here even. it's the opposite and it's never mentioned before. all im asking is whether or not the number of drives IN A NON RAID ENVIRONMENT would improve vm disk performance in xenserver.
    – user128049
    Jul 12, 2012 at 10:31
  • And the answer is "it depends".
    – womble
    Jul 12, 2012 at 10:38
  • depends on what exactly?
    – user128049
    Jul 12, 2012 at 10:43

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