Re: Redo log & RAID

There are several options:

1. Hardware Mirroring.
2. OS Mirroring
3. Oracle mirroring.
4. Combinations of the above.

Each of the above has advantages and disadvantages. However, redo logs are critical for both performance and reliability. During updates, the faster you make them, the faster the database runs (generally speaking).

What you do depends on your applocation. For example, are you running in archive log mode? No -> why mirror them anyway? Is data recoverability critical? How important is performance? How many updates are happening?

Depending on needs, I recommend between 1 an d12 (yes twelve) disks for redo logs. For performance, I recommend solid state "disks" (memory with battery backup). For the ultimate in reliability, I recommend to clients that the use BOTH oracle and hardware or OS mirroring.

In short, I would choose oracle miror over OS or hardware mirror for reliability and hardare for performance (or better yet. solod state hardware). There IS a performance hit for oracle mirroring. However, you will only notice this if your system is close to saturation. For other systems, the point is irrelavant.

Are you even more confused?

"Roger Menhennett" <r.menhennett_at_lmco.com> wrote in message news:3AC4BEB8.FECC027D_at_lmco.com...
> Oracle mirrors its redo logs with multiple members per redo log group,
> advisedly
> with each member on a separate disk. Question: is HW or SW mirroring a
> better alternative to Oracle's mirroring of these files?
>
Received on Sun Apr 01 2001 - 17:27:19 CDT