Re: Tablespaces on a raid configuration

On Fri, Mar 30, 2012 at 8:45 AM, Campbell, Lance <lance(at)illinois(dot)edu> wrote:

> PostgreSQL 9.0.x****
>
> When PostgreSQL storage is using a relatively large raid 5 or 6 array is
> there any value in having your tables distributed across multiple
> tablespaces if those tablespaces will exists on the same raid array? I
> understand the value if you were to have the tablespaces on different raid
> arrays. But what about on the same one?****
>
>
>
Our application is a combination of OLTP and OLAP. We've successfully
split the database into 3 different tablespaces.

1. RAID Group A is RAID 10 contains /var/lib/pgsql/data and the OLTP
database (default tablespace)
2. RAID Group B is a RAID 10 for the indexes on the data warehouse (index
tablespace)
3. RAID Group C is a RAID 5 containing the actual data warehouse (data
tablespace)

A more optimum configuration would include another RAID 10 for the indexes
for the OLTP but we ran out of drives to create a RAID Group D and the
above configuration works well enough.

Before going with RAID 5, please review http://www.baarf.com/.

-Greg