Re: Performance Impact of going from 2 parity drives to 4paritydrives in a 4-disk RAID set

Chris Bipes wrote:

Write to disk 4 - stripe to disk 1-3

Chris:

I think it would more accurately be something like:

> Write to disk 4 - stripe to disk 1, 2 or 3 depending on which one held the parity for that block...

...and:

Write to disk 4 - stripe to disk 2 or 3 depending as above...

As you can see disk 2 and 3 get heavily hit while 1 and 4 may not.

OTOH, there will never be 'normal' reads/writes to the blocks with parity stripes on 2 and 3 during 'normal' data access. I.e., disks 2 and 3 will have less access that isn't involved in RAID striping.

I suspect that your best course will be to wait until you have both some statistics and some spare system time.

Tom Liotta