We're deploying a few new V7000 systems (previously using Gen2 XIV). All SAS 900GB 10K drives plus some SSD for EasyTier.
Vendor / IBM has advised that we should be using RAID5 RAID groups (mdisks in V7000/SVC nomenclature I guess). Sounds like there are some solid reasons for doing this, but there's some internal hesitation around these larger drives and whether or not we should be using RAID6 instead.
Some of the reasons we've been given to accept any risks that go along with RAID5 are that we're using relatively small RAID groups, rebuild times on the V7000 are very quick (<1hr?) due to the RAID group size and other optimizations in the Storwize stack, and that disks are "pre-failed".
Any thoughts/feedback from the field? Obviously we'd for sure go RAID6 if we were using NL-SAS....