Re: NAS, SAN or any alternate solution ? - Mailing list pgsql-performance

From Rod Taylor
Subject Re: NAS, SAN or any alternate solution ?
Date
Msg-id 1095886379.24440.56.camel@jester
Whole thread Raw
In response to Re: NAS, SAN or any alternate solution ?  (Andrew Hammond <ahammond@ca.afilias.info>)
List pgsql-performance
> Rod Taylor wrote:
> | I've used both a NetApp and Hitachi based SANs with PostgreSQL. Both
> | work as well as expected, but do require some tweeking as they normally
> | are not optimized for the datablock size that PostgreSQL likes to deal
> | with (8k by default) -- this can make as much as a 50% difference in
> | performance levels.

> I'm also not entirely sure how to make the datablocks line up with the
> filesystem blocks. Any suggestions on this would be greatly appreciated.

We just played with Veritas settings while running pg_bench on a 200GB
database. I no longer have access to the NetApp, but the settings for
the Hitachi are below.

In tunefstab we have:

read_pref_io=8192,read_nstream=4,write_pref_io=8192,write_nstream=2

In fstab it's:
    defaults,mincache=tmpcache,noatime


If you have better settings, please shoot them over so we can try them
out. Perhaps even get someone over there to write a new SAN section in
the Tuning Chapter.


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