Checking filesystems periodically

Martin Langhoff martin.langhoff at
Mon May 7 11:34:50 EDT 2012

On Fri, May 4, 2012 at 9:41 AM, Daniel Drake <dsd at> wrote:
> Thirdly, fsck is not magic. It cannot detect/repair all corruption. As
> far as I know, we have not yet found a case of corruption which can be
> meaningfully fixed by fsck. We did do quite a bit of testing for this
> at an earlier point.

It is worthwhile expanding on this: ext3 is a journalled fs, so it can
fix _some_ issues thanks to the journal, and does so on boot. So the
"harsh environment" issues are mostly handled by ext3 journal-based

For problems not fixable with ext3's journal-based recovery... cannot
(currently) be fixed by fsck as dsd writes. At least that's what we
found so far.

Given those findings, it fell in our priorities list, and there is
harsh competition there! :-)

Now, fsck and our choice of FS are not frozen in stone, so help is
welcome on this track. Improving our plymouth screens to have an "I'm
doing extra work this time, so booting slower" image would be good.
Not easy, but definitely good.

(Note that any boot time repair must be fully automated. 6 year olds
won't be telling fsck what to do with the broken inode table.)


 martin.langhoff at
 martin at -- Software Architect - OLPC
 - ask interesting questions
 - don't get distracted with shiny stuff  - working code first

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