Well, conventional circa-1994 "raid 5" is completely inappropriate for
oltp, I'd agree 100%. Modern "raid-5" disk configurations, as they're
called by some vendors, might actually be "raid 3" configurations, which I think are
pretty good alternatives to use. Raid 3 is essentially raid-0 disks with
all the parity written to an additional disk.

Do a google search on "what is raid 3" to find some nice example pages.

boss

>
> "Never use raid 5 on Oracle OLTP DB" is SO NOT TRUE now a days. Although RAID 3 or 5 is certainly NOT the best choice for redo or temp tablespaces, many of todays RAId subsystems with proper config and caching can perform quite nicely. I have a test system where then ENTIRE db/app is on ONE RAID 5 and it runs very well considering it's just test. If you have the hardware and dollars, yada yada yada, go ahead and config RAID 0, 0+1, 10, or whatever. Not all companies can nor is it always appropriate. If you are trying to squeeze every drop of performance out of the system and can do/afford a mirror/stripe, then by all means do so. But to say NEVER, just incites rants like this one...
>
> >>> "Givon Yoav " <oracledba-ezmlmshield-x88333983.[Email address protected] 06/02/04 06:42AM >>>
> Never use raid 5 on Oracle OLTP DB. Calculating the CRC cost U numerous
> CPU cycles and will slow down your write I/O operations. Use striping
> and mirroring instead (Raid 0+1).
>
> Use more then one DBW if your existing one is exhausted BUT your I/O sub
> system can handle the extra I/O of the second DBW. Definably not the
> case in Raid 5 environment.
>
>
> Yoav
>
>
> -----Original Message-----
> From: Aldo Judeel
> [mailto:oracledba-ezmlmshield-x92441541.[Email address protected]
> Sent: Wednesday, June 02, 2004 11:19 AM
> To: LazyDBA.com Discussion
> Subject: DBW0 and RAID5
>
> Can anyone please tell me if more that one DBW process will be a benefit
>
> On a RAID5 system with only one CPU?
>
>
>
> Tkanks
>
> Aldo
>
>
>
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