Re: Configuring RAID for best Oracle performance

In article <pinnacle-0501950848470001_at_hou01.onramp.net>, pinnacle_at_onramp.net (Pat Kelly) wrote:

> How should I configure a new RAID subsystem to balance the opposing
> requirements of good Oracle performance and good data availablity?

Good question. My group is working out a "best answer" for the Digital platforms, but I think some general principals apply.

Log disks: the only RAID level that really makes sense is RAID 1 (shadowing). In fact, RAID is pretty cool for this. You *have* to have your redo logs mirrored/shadowed in some way. Best to push the work as close to the physical disk drive as possible. Yeah, you could do Oracle mirroring or O/S-level shadowing, but RAID 1 is probably the least overhead on the system and hence the best performer. I wouldn't use any other level of RAID on a log disk.

Data disks: depends on your needs and what you have. Just remember, you're buying RAID to cover your butt in case of a disk failure. Test it that way. Not only do you need to think about configuring RAID with all disk drives working, you also need to think about the performance level that you can stand if you lose a disk drive. This may change how you configure RAID. There are too many different implementations of RAID (levels, cache sizes and algorithms, number of disks) for me to give any sort of recommendation. Take the RAID vendors to task: have them drop a unit off at your place and play with it a while.

Good luck.

-- 
Jef
  "...I wouldn't normally do this kind of thing." -- Pet Shop Boys