Thread: raid setup for db

From:
Thomas Finneid
Date:

Hi

I am wondering what stripe size, on a raid 0, is the most suitable for
postgres 8.2?

I read a performance tutorial by Bruce Momjian and it suggest setting
the stripe size to the same block size (as pg uses?)
( http://momjian.us/main/writings/pgsql/hw_performance/index.html )
But I want to check whether I have understood this correctly.

Are there any other hot confguration tips I should consider or does
anybody have any suggestions for other raid configuration articles?

regards

thomas

From:
Scott Marlowe
Date:

On Wed, May 13, 2009 at 1:51 AM, Thomas Finneid <> wrote:
> Hi
>
> I am wondering what stripe size, on a raid 0, is the most suitable for
> postgres 8.2?
>
> I read a performance tutorial by Bruce Momjian and it suggest setting the
> stripe size to the same block size (as pg uses?)
> ( http://momjian.us/main/writings/pgsql/hw_performance/index.html )
> But I want to check whether I have understood this correctly.
>
> Are there any other hot confguration tips I should consider or does anybody
> have any suggestions for other raid configuration articles?

8k is a pretty small stripe size.  If you do anything that needs seq
scans, a larger stripe size generally helps.  It's probably more
important to align the file system's block size to the underlying RAID
than to worry about the pg block size too much.  Common values that
have been posted here running fast for both random and sequential
access have been in the 32k to 256k range with some outliers on the
high end doing well.

From:
Rafael Martinez
Date:

Thomas Finneid wrote:
> Hi
>
> I am wondering what stripe size, on a raid 0, is the most suitable for
> postgres 8.2?
>

Hello

Raid 0 for a database? This is a disaster waiting to happen.
Are you sure you want to use raid0?

regards
--
 Rafael Martinez, <>
 Center for Information Technology Services
 University of Oslo, Norway

 PGP Public Key: http://folk.uio.no/rafael/

From:
"Thomas Finneid"
Date:

Dont worry about it, this is just for performance testing.

thomas

> Thomas Finneid wrote:
>> Hi
>>
>> I am wondering what stripe size, on a raid 0, is the most suitable for
>> postgres 8.2?
>>
>
> Hello
>
> Raid 0 for a database? This is a disaster waiting to happen.
> Are you sure you want to use raid0?
>
> regards
> --
>  Rafael Martinez, <>
>  Center for Information Technology Services
>  University of Oslo, Norway
>
>  PGP Public Key: http://folk.uio.no/rafael/
>
> --
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