Message-ID: <3B662642.4AB6E800@zip.com.au>
Date: Tue, 31 Jul 2001 13:30:10 +1000
From: Andrew Morton <akpm@zip.com.au>
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To: Tony.Lill@ajlc.waterloo.on.ca
CC: linux-kernel@vger.kernel.org
Subject: Re: laptops and journalling filesystems
In-Reply-To: <200107310254.WAA22236@spider.ajlc.waterloo.on.ca>
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Sender: linux-kernel-owner@vger.kernel.org
Original-Recipient: rfc822;linux-kernel-outgoing

Tony Lill wrote:
> 
> Do any of the current batch of journalling filesystems NOT diddle the
> disk every 5 seconds? I've tried reiser and ext3 and they're both
> antithetic to spinning down the disk. Any plans to fix this bug in
> future kernels?

If you mount everything with `noatime' there's nothing to
be written unless you're writing stuff.

Unfortunately ext3 defeats the trick of setting the kupdate
interval to something huge.  On my list of things-to-do.

Probably it's as simple as setting the commit timer to
a large interval (grep for "HZ" in fs/jbd/journal.c).

Commits are driven by either a timer expiry or by the
journal getting too full.  If the interval is set large
then probably journal-full will be the main reason for
running a commit.

Of course, if the interval is set to 15 minutes and
you crash, you'll lose up to 15 minutes' work.

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