Re: moving pg_xlog -- yeah, it's worth it! - Mailing list pgsql-performance

Kevin Grittner wrote:

> Another example of why I shouldn't trust my memory.  Per the
> hardware tech:
>
>
> OS:      /dev/sda   is RAID1  -  2  x  2.5" 15k SAS disk
> pg_xlog: /dev/sdb   is RAID1  -  2  x  2.5" 15k SAS disk
>
> These reside on a ServeRAID-MR10k controller with 256MB BB cache.
>
>
> data:    /dev/sdc   is RAID5  -  30 x 3.5" 15k SAS disk
>
> These reside on the DS3200 disk subsystem with 512MB BB cache per
> controller and redundant drive loops.

Hmm, so maybe the performance benefit is not from it being on a separate
array, but from it being RAID1 instead of RAID5?

--
Alvaro Herrera                                http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support