Re: laptops and journalling filesystems

[Andrew Morton]

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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