- HP 2012i SAN,
- 7 disks in RAID 5 with 1 hot spare,
- took several days to expand the volume from 5 to 7 300GB SAS drives.
Looking for suggestions about when and how I would determine that having 2 volumes in the SAN, each one with RAID 5, would be better??
I can add 3 more drives to the controller someday, the SAN is used for ESX/vSphere VMs.
Thank you…
Best Answer
I've wrestled with this question for a while. There are a number of factors determining how many disks should go into a RAID5 array. I don't know the HP 2012i, so here is my generic advice for RAID5:
RAID6 (double parity) is a way to get around the non-recoverable read error rate problem. It does increase controller overhead though, so be aware of the CPU limits on your controllers if you go there. You'll hit I/O bottlenecks faster using RAID6. If you do want to try RAID6, do some testing to see if it'll behave the way you need it to. It's a parity RAID, so it has the same performance penalties for rebuilds, expansions, and restripes as RAID5, it just lets you grow larger in a safer way.