Re: To RAID or not to RAID (...or how to RAID)

"Rick Denoire" <100.17706_at_germanynet.de> wrote in message news:gecvnukn3tp03pkted9c0rqgln1vokg25i_at_4ax.com...
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Hi

>
> I am planning to put an Oracle DB (8.1.7, Solaris 2.7) on a RAID
> System from Dell with 10 HDs in a RAID 1/0 configuration.
>
> My question is, should I make one logical device out of all disks and
> just put all tablespaces there? Or should I make groups of disks
> holding different kind of data?

This is an interesting question for me as I just had the opportunity to consider this on a new system we built. What we did was to seperate the tablespaces (which are defined by the vendor's application) onto seperate raid volumes. Yes it was expensive in disk. This mirrored the way the prior version of the app had been setup by the vendor. The logic here is that the data is split by type of access (static tables,historic tables,transactional tables etc). What I wanted to do was to create one huge raid volume for data and stripe across many disks the logic here is that in the SAME paper. Then I wanted to benchmark the performance with the system setup both ways.

I had two problems with this.

1. What is a suitable benchmark? I decided that a days worth of sql extracted from running logminer against the previous db might be appropriate.
2. Time vs benefit. I suspect that organising data optimally as opposed to 'well enough' would be likely to produce performance gains of in the order of 5%. tuning indexes, memory, sort etc will give me better results.

So if you can identify a suitable benchmark, and have the time I'd say do the experiment. If time and effort is short go with your standard build and concetrate on the application. that is where you'll derive most benefit.

--
Niall Litchfield
Oracle DBA
Audit Commission UK
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