Re: stipe size

From: Paul Drake <discgolfdba_at_yahoo.com>
Date: Fri, 20 Feb 2004 12:09:17 -0800 (PST)
Message-ID: <20040220200917.63782.qmail@web20419.mail.yahoo.com>

Ruth Gramolini <rgramolini_at_tax.state.vt.us> wrote:
> Good morning all,
> We just installed a new fast disk farm with fiber
> channels. For production
> we are using raid 10. My SA set in up with a stipe
> size of 64K based on the
> size of most of the transactions. He wants to know
> if this will be OK. I
> don't know so I told him I would ask the experts.
> What do you think?
>
> Thanks,
> Ruth Gramolini
> Oracle DBA
> Vermont Department of Taxes

Hi Ruth.

I'm not claiming to be an export, but I'll chime in anyways. :)

What operating system and version are you running Oracle Server on?
What is the database block size?
What filesystem are you using, or are raw volumes in use?
Does the storage unit have a cache that is used for pre-fetching, and does it also support write-back cacheing?
How many drives comprise the striped volume?

In an average statspack report, what is the average number of blocks fetched per request in your data, index and temp tablespaces?

If you're performing mostly single block accesses, then a smaller stripe size will carry the least overhead, but may make maintenance operations take longer.

It will be a tradeoff of optimizing performance of daily oltp activity (single block requests), vs. your monthly batch jobs which are likely more batch-oriented, which may favor a largish stripe size, say 512KB.

I'd highly recommend that he short-stroke the drives, and only throw a filesystem on the outer half of the disks for datafiles, and throw a filesystem on the inner half for storing backups, archlogs, etc.

Paul

token reference to Juan Loiza's paper on SAME up on the BAARF.net site

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Received on Fri Feb 20 2004 - 15:24:12 CST