Re: Need help with redo log writer

Flyfish <d_at_deja.com> wrote:
>
>The striping is in fact, Raid 5, unfortunately not subject to change as
>the system owner 'requires' raid 5 for reliability.

Ouch. They can't be talked out of this in any way? Tom Kyte mentioned a very nice redo setup with 5 disks recently:

1. log group 1,3,5...
2. log group 2,4,6...
3. log group 1,3,5...
4. log group 2,4,6...
5. Archive

This gives resistance against single disk failure for online logs, which is all you get from RAID-5, and offers a fair chance of surviving two failures. You could obviously mirror the archive area for single disk failure resistance.

If you're stuck with it regardless, you have my sympathy for trying to tune a system that's got a large anchor tied to it.

-- 
Andrew Mobbs - http://www.chiark.greenend.org.uk/~andrewm/