Re: implementing soft-updates

From: Andreas Dilger (adilger@clusterfs.com)
Date: Mon Apr 15 2002 - 15:47:09 EST


On Apr 08, 2002 20:35 +0000, Pavel Machek wrote:
> Andi Kleen writes:
> > You can already do background fsck on a linux system today. Just do it on
> > a LVM/EVMS snapshot.
>
> How do you fix errors you find by such background fsck?

You shouldn't get any in the first place (they would be from disk
errors, memory corruption, software bugs, etc). If you _do_ get such
an error, isn't it worth it to shut down your system and bring it back
to a known state (and maybe figure out what actually caused this error)?

The only reason to have such a feature is for high-availability,
high-uptime systems which cannot normally be shut down. In very recent
versions of e2fsprogs, you are able to reset the "last checked" field
in the superblock (you could reset the "mount count" field for a long
time), so that you do an online check every week/month, then you can
avoid the forced fsck after a reboot because the filesystem hasn't been
checked in 6 months.

Cheers, Andreas

--
Andreas Dilger
http://www-mddsp.enel.ucalgary.ca/People/adilger/
http://sourceforge.net/projects/ext2resize/

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