Subject: Re: Limiting disk I/O?
To: Michael van Elst <email@example.com>
From: Steven M. Bellovin <firstname.lastname@example.org>
Date: 11/13/2007 00:18:17
On Mon, 12 Nov 2007 20:38:10 +0000 (UTC)
email@example.com (Michael van Elst) wrote:
> firstname.lastname@example.org (Jukka Marin) writes:
> >Wow :-) But I don't think delaying a catastrophe is the same as
> >preventing it :-) I would like to slow down the sync operation (to
> >leave part of the I/O capacity for other things). I guess I could
> >try making the delays real short and see what happens then..
> The problem comes from running out of buffers. You want to sync
> often and you want to sync fewer buffers in a burst to mitigate
> the problem.
This, I think, is a large part of the actual solution to the problem.
The other part is to have the process scheduler penalize processes -- or
users? -- that do too much I/O.
--Steve Bellovin, http://www.cs.columbia.edu/~smb