We encountered an interesting situation up here recently, and it generated a lot of debate between the PSC’s. We finally locked down the answer, and I figured I would write it
up and spread the knowledge!
The issue was that a RAID DP group on a system had 13
450GB data drives, 1 450GB Parity drive, 1 600GB data drive, and 1 600GB DP
drive. The data drives were all right-sized to the same “effective used”
size, but the 600GB DP drive was showing as not right-sized. This was in
debate because it was commonly believed that all disks within a single RAID
Group were required to be the same effective size.
In an amazing FAQ document (please find it attached),
we found the following:
The document is written by Jay White, a Technical
Marketing Engineer widely regarded as the authority on NetApp storage
subsystems. It’s a fascinating series of scenario studies that comes
highly recommended.