Re: table spaces

On Sat, Mar 9, 2013 at 10:51 AM, Gregg Jaskiewicz <gryzman(at)gmail(dot)com> wrote:
> Performance related question.
> With Linux (centos 6.3+), 64bit, ext4 in mind, how would you guys go about
> distributing write load across disks.
>
> Lets say I have quite few disks, and I can partition them the way I want, in
> mirror configuration (to get some hardware failure resilience). Should I
> separate tables from indexes onto separate raids ?
>
> I know WAL has to go on a separate disk, for added performance.
>
> I'm looking for your experiences, and most importantly how do you go about
> deciding which way is best. I.e. which combinations make sense to try out
> first, short of all permutations :-)

First get a baseline for how things work with just pg_xlog on one
small set (RAID 1 is often plenty) and RAID-10 on all the rest with
all the data (i.e. base directory) there. With a fast HW RAID
controller this is often just about as fast as any amount of breaking
things out will be. But if you do break things out and they are fster
then you'll know by how much. If it's slower then you know you've got
a really busy set and some not so busy ones. And so on...