[nylug-talk] Ext3 Disk Reservation and Defaults -- WAS: extfs journalling percentage

[Chris Knadle]

On Thursday 29 May 2008, Bryan J. Smith wrote:
> Chris Knadle wrote:
> > Ah.  Yeah, at boot time the normal periodic fsck of ext3, when I
> > used it, usually noted about 4% "non-continuous", i.e. fragmentation,
> > if I remember correctly.
> >
> > I'm mostly using XFS currently, in which an fsck at boot time is
> > essentially a no-op.
>
> Unlike Ext3, XFS actually does many things simultaneous with mounting.
> Unfortunately, sometimes XFS will mount, then realize its meta-data
> journal replay has failed.  It will then make itself unavailable, after
> already making itself available.
>
> I assume you've never had to run "xfs_repair", it's off-line fsck?  ;)

   I have.  One box I have managed to corrupt an XFS filesystem.  xfs_repair 
managed to get it back at least into a usable state so that I could replace 
the system packages that had damaged files.

   I understand that XFS gets checked upon mount instead at boot-time fsck, 
which is why I worded the prior email the way I did.  I wasn't trying to 
imply that an XFS filesystem never required checking.

> BTW, one of the reasons I _never_ used ReiserFS is because their
> off-line fsck was constantly "out-of-sync" with the in-kernel,
> structural implementations.  So even if ReiserFS was solid in the
> kernel, and its meta-data journaling was often, if the journal replay
> failed, you were at the mercy of its off-line fsck.
>
> It wasn't pretty every time I had to drop to that.

   I've tried ReiserFS in test cases, but never used it in production.  The 
problem ReiserFS v3 had with corruption upon unmount and the lamenting on the 
Linux Kernel Mailing List conerning ReiserFS is mostly what kept me from 
wanting to try it for more serious use.

   -- Chris

-- 

Chris Knadle
Chris.Knadle at coredump.us