Re: Oracle Performance on RAID 5

Mirrored disks can in fact slow 'writes' down, as the data has to be sync'ed between both drives. I'd suggest looking at striping and/or RAW devices for improved write performance for TEMP. Obviously look at mirroring if you want FT as well. Oh, and test a number of configurations, as all databases and hardware/software mixes are different.

One point worth noting about your TEMP tablespace is that you can always drop it and recreate it if you hit problems, unlike all the other data files and logs, so mirroring it may not be necessary. It all depends on your up-time requirements.

Once last point: note what was said about the poor write performance of RAID5 on writes (i.e. not good for TEMP and redo - or bulk updates, if you do a lot of that).

MotoX.

Robert Hart wrote in message <3587a775.0_at_champ>...
>Hi
>
>I was actually thinking of putting my temporary Tablespace
>on mirrored disk too. I haven't decided yet because
>this system is VERY mission critical. Looking at it that
>way I lean towards doing it all RAID5.
>
>Rob Hart
>
>Han Brinkman wrote in message

<898072402.188302_at_jive.news.big-orange.net>...
>>What I have heard from a hardware vendor is that when your I/O is
>consisting
>>more than 30% of write actions Raid-5 is slower because of the overhead of
>>writing the parity.
>>I think a that case your rbs and redo files should be on a mirrorred disk
>>and your normal db files could reside on a raid-5 fs.
>>
>>Han Brinkman
>>
>>
>>
>
>
Received on Thu Jun 18 1998 - 06:44:34 CDT