Re: Oracle on Digital Unix RAID

Bryan -

We have been getting great performance from RAID-5 under OSF/1 3.2 (Oracle 7.1.6.2). Writes are a little slower than RAID-1 but reads make up for it.

Is it possible when you planned your database you considerd the RAID-5 spindles as anything other than a single (logical) drive? We have multiple RAID-5 arrays and manage each as if they were single spindles. That's how we laid out our database and performance is fine.

If you are using a single RAID-5 array then I would agree with your point - especially if you have a single point of entry (i.e. controller) to it.

FWIW, no vendor of RAID-5 I have spoken to has ever recommended it as a performance booster. I think if they could reach the same overall (read/write) as single spindles we would all be quite pleased. After all, the point is fault resiliency, right?

Regards,
jh

Bryan Lenihan wrote:
>
> We are currently running on a RAID 5 system and are having trouble with
> performance. Oracle and it technologies are not friendly with a RAID 5
> system. We are in the process of seperating our RAID 5 system and setting
> all the disks to a RAID 1 system. This is a costly method, but my company
> wants to have redundant disks for zero downtime.
>
> I would recommend that you do not run on a RAID 5 system. Most operating
> systems have a system performace downgrade when using RAID 5. To Oracle a
> RAID 5 looks and acts like 1 disk drive, you will have disk contentions,
> controller contention and user contentions.
>
  Received on Thu Sep 05 1996 - 00:00:00 CEST