Subject: Re: Limiting disk I/O?
To: Tech-kern <email@example.com>
From: Joerg Sonnenberger <firstname.lastname@example.org>
Date: 11/12/2007 13:16:39
On Mon, Nov 12, 2007 at 09:24:34AM +0200, Jukka Marin wrote:
> Is there a way to limit the number of transfers to disk per second? Or
> better yet, a way to limit the disk load ("%busy" in systat) to, say, 90%?
> Ideally, this should probably affect only ioflush, so other disk accesses
> would still be possible. Or maybe there's an even better way of preventing
> the cache flush from overloading the disk(s)?
Have you tried using a different IO scheduler? There are kernel options
to give priority sorting and read-optimised scheduling. You can select
the policy for a device with dkctl $dev strategy. The default is first
come, first serve. It can also help to disable softdep :-)