Re: Raid Configurations and Oracle

==========mthomas_at_digital.net, 9/23/96========== Are there any white papers or the like on this topic?

We are going to 2 Raid-5 5 disk arrays (I know, that's redundant!) with hopefully 1 or 2 Raid-1 devices (in other words, 1 or 2 disks that will be mirrored). However, there may only be the RAID-5 arrays... it's not resolved yet.

We are using Silicon Graphics Challenge RAID arrays...although I would like to hear of experiences on any RAID-5 and/or RAID-1. Tell me the good as well as the bad!!

Thanks,
Mary Thomas

Mary,

My experience comes from using an NCR 3550 system configured as Raid 5. Under this configuration, daily hot backups took 10+ hours to complete a 14GB database. As you can appreciate, this was intolerable. We reconfigured the system by going to Raid level 1 only, and the hot backup time dropped to 5 hours and the users noticed a decrease in the length of queries.

By going to Raid level 1, we cut our available Raid storage down by half, but it was worth it. There seems to be considerable controller overhead in running Raid 5. Consider this as you plan.

In all fairness, though, please realize our backup methodology is not cutting edge. We are using the Unix dd command. Soon we will suppliment our backup strategy with new Digital Linear Tape Drives. Estimated backup times for a 20GB database is 3.17 hours.

Best of wisdom,
David Jordan Received on Wed Sep 25 1996 - 00:00:00 CEST