Subject: Re: comparing raid-like filesystems
To: Jukka Marin <jmarin@pyy.jmp.fi>
From: Antti Kantee <pooka@cs.hut.fi>
List: current-users
Date: 02/01/2003 11:08:32
On Sat Feb 01 2003 at 10:04:25 +0200, Jukka Marin wrote:
> I have no experience of the RAID controllers, but I'm not particularly
> happy with the NetBSD RAIDframe implementation.  I bought fast disks,
> configured RAID - and found out that RAID drops the performance to a
> fraction of that of the disks.
> 
> I don't know why, because when RAID is 100% busy, CPU load is almost
> zero and the disk load 25% or so.  It's like if RAIDframe had some
> usleep() calls in the code to make things go slower..

What's your stripe unit size? I also was suffering from inexplainable
slowness until I dropped the stripe unit size to 16 sectors. Before that
my RAID5 gave something like 5MB/s write speeds, now it's giving more
than 25MB/s.

-- 
Antti Kantee <pooka@iki.fi>                     Of course he runs NetBSD
http://www.iki.fi/pooka/                          http://www.NetBSD.org/
                 "connoisseurs do not chill their malts."