Re: Oracle Performance on RAID 5

Use RAID 0+1 and get the best of both worlds. You get the performance improvements of striping, without the heavy cost on writes you get with RAID 5.

	Chuck Hamilton
	chuckh_at_dvol.com

On Thu, 18 Jun 1998 08:09:54 -0600, "Robert Hart" <rhart_at_gov.edmonton.ab.ca> wrote:

>Hi
>
>Yes I did note the poor write performance of RAID5
>for writes. I am more concerned about the read
>performance. From what I read you should have
>very good read performance unless your stripe
>size is too small.
>
>I know that keeping my redo logs, Temp tablespace
>or any other write intensive areas off the RAID 5 will
>improve the performance. Still, I will probably put it all
>on RAID5 and have a hot standby drive in the
>array. I know it will slow it down but this is a Dispatch
>system for Ambulance/Fire and if it is down there could
>be a drop in the response time for our Ambulance
>and Fire crews. So this System MUST be up.
>
>What concerns me is Vendor claims that I will suffer
>a performance hit on reads. All the literature I've read
>indicates that this is not true. My experience on RAID5
>has been good. No read performance degradation in
>my experience. I'm just asking if anyone has had
>a drop on read performance for reads.
>
>l8r
>Robert Hart
>
>MotoX wrote in message
><898170190.23434.0.nnrp-09.c2de712e_at_news.demon.co.uk>...
>>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.
>>
>>
>
>

--
Chuck Hamilton
chuckh_at_dvol.com

If at first you don't succeed, sky diving isn't for you. Received on Fri Jun 19 1998 - 10:25:16 CDT