Our F760 has 6 shelves and 42 36GB drives (running Data OnTAP 6.3.3 if that matters). Four volumes have been configured, with one RAID group in each volume; two have eight disks each, one has seven, and one that is mostly inactive archived stuff has four disks. That leaves fifteen (count 'em, 15) spares.
All the volumes except the archive are at or near 90% of capacity, a point at which I understand performance starts to plummet, and the storage needs of the users of the three active volumes continue to increase.
What is the optimal way to make use of the oversized pool of spares? Thoughts I've had:
- Create a new volume, put new projects there, and maybe move some projects over from existing volumes, so everyone who needs it has room to grow.
- Add disks to the existing volumes gradually as needed, to keep capacity under 90%. If I do this, is it better to add new disks one at a time or several at once? Is going over 90% really a problem, or is that just unfounded rumor?
Other suggestions are welcome. Also, how many spares would it be appropriate to keep as spares? I've been told that one per shelf would be enough, but some postings in the archives indicate that that may be on the generous side.
Thanks!