Re: What level of RAID for Oracle WorkGroup Server 7.3?

Juergen Schiewe wrote:

> Mirroring is less helpful than it may seem. If a datafile is corrupted > by a database error or accidently deleted by a dba it is also
> corrupted or deleted on the mirror disk.

True, but then how often does a DBA jump in and start deleting parts of the database! :-)

Mirroring is really there to protect you from *hardware* failure. Mirrored drives, in their own cabinets, with there own power supplies, and their own disk controllers, can be extremely effective. You also have the option of breaking parts of a mirrored group away temporarily for backup purposes. You also retain the ability to very finely tune the disk I/O distribution of your database as you see fit, unlike RAID.

However, striping can also be useful for boosting performance. Oracle's own recommendation on their VLDB seminar was to consider a mix of RAID 0+1 disk sets. RAID 5 was generally frowned upon because of the hit in 'write' performance, although for query intensive databases, i.e., datawarehouses, the increased 'read' performance of RAID 5 may be a deciding factor.

I'd be interested to hear of anyone elses opinion of RAID v non-RAID setups.

Steve Phelan.

Steve Phelan. Received on Tue Mar 25 1997 - 00:00:00 CST