Subject: Re: FFSv1 performance on large filesystems
To: None <tech-kern@NetBSD.org, tech-perform@NetBSD.org>
From: Matthias Scheler <tron@zhadum.de>
List: tech-kern
Date: 03/24/2005 02:25:22
On Wed, Mar 23, 2005 at 07:13:49PM -0600, Greg Oster wrote:
> > No, it's RAID-1. But writes should still happen in parallel there.
> They do.
RAIDframe queues them in parallel. But maybe something in the kernel
searilizes them?
> What does your raid0.conf file look like?
The RAID gets autoconfigured. But the configuration file I used for
creating it looked like this:
START array
1 2 0
START disks
/dev/wd0a
/dev/wd1a
START layout
128 1 1 1
START queue
fifo 100
> I'd expect a RAID 1 set to write a little slower than the raw disk,
> but not this much slower.
Yes, me too. It should be slower by the latency it takes to deliver the
write to the second disk. But not by a factor of two.
> I'd also be interested in ccd(4) results (with the same stripe
> widths...)
It's not a stripe it's a mirror.
Kind regards
--
Matthias Scheler http://scheler.de/~matthias/