Re: Need advice on RAID5

There seem to be different opinions on using RAID5 technology for Oracle databases. A lot of people are using it without any problems, but i also got reply's from people warning me not to use RAID5.

After reading your responses and reading some articles about RAID, i come up with the followong conclusions:

1. RAID 5 degrades write I/O performance significantly. So, putting heavily updated tablespaces (which is the case for OLTP systems) on a RAID5 volume will affect response times. If response times are not acceptable for your users and you do need data storage reliability RAID 0+1 (mirroring and striping) is a good alternative.
2. The same thing goes for temporary tablespaces, which are typicaly written to extensively. One might consider RAID0 (striping) here for improved performance.
3. For tables wich are accessed most of the time for read operations RAID5 is the solution (improved reliabiltiy and performance).
4. If response times aren't critical, high availability is, and you don't want to waste disk space on mirroring, one could consider RAID5 to be an option. Using raw devices migth speed up things a bit here.

Please correct me if i'm wrong in anyway. I don't consider myself to be an Oracle expert nor a RAID expert.

Rob Heemskerk
GAK
The Netherlands
e-mail: rheemske_at_gak.nl Received on Wed Oct 11 1995 - 00:00:00 CET