Re: [ADMIN] H/W RAID 5 on slower disks versus no raid on

Björn Metzdorf <bm@turtle-entertainment.de>

From: "Bjoern Metzdorf" <bm@turtle-entertainment.de>
To: "scott.marlowe" <scott.marlowe@ihs.com>
Cc: <pgsql-performance@postgresql.org>
Date: 2002-11-21T21:57:59Z
Lists: pgsql-performance
> Generally RAID 5.  RAID 1 is only faster if you are doing a lot of
> parellel reads.  I.e. you have something like 10 agents reading at the
> same time.  RAID 5 also works better under parallel load than a single
> drive.

yep, but write performance sucks.

> The fastest of course, is multidrive RAID0.  But there's no redundancy.

With 4 drives I'd always go for raid 10, fast and secure

> Oddly, my testing doesn't show any appreciable performance increase in
> linux by layering RAID5 or 1 over RAID0 or vice versa, something that
> is usually faster under most setups.

Is this with linux software raid? raid10 is not significantly faster? cant
believe that...

Regards,
Bjoern