On gjournal vs unexpected shutdown (-->fsck)

[Andrew Reilly]

On Tue, Dec 15, 2009 at 09:49:56PM +0000, Hywel Mallett wrote:
> 
> On 8 Dec 2009, at 22:47, Andrew Reilly wrote:
> 
> > Hi there,
> > 
> > I thought that I'd try a gjournal'd UFS on one of my spare
> > drives (so: dedicated to the task, formatted from clean, per the
> > instructions in the gjournal man page.)  The filesystem itself
> > seems to be working swimmingly, although it isn't heavily used.
> > In the time that I've had it running, though, I've had two power
> > outages that have resulted in unexpected shutdowns, and I was
> > surprised to find that the boot process did nothing unexpected:
> > file system not marked clean: fsck before you can mount.  So
> > both times I fsck'd the drive, and as near as I can tell this
> > took exactly as long as fsck on a regular UFS system of similar
> > size.  Isn't the journalling operation supposed to confer a
> > shortcut benefit here?  I know that the man page doesn't mention
> > recovery by journal play-back, but I thought that it didn't need
> > to: that's the whole point.  Is there a step that I'm missing?
> > Perhaps a gjournal-aware version of fsck that I should run
> > instead of regular fsck, that will quickly mark the file system
> > clean?
> > 
> > (Running -current as of last weekend, if that matters.)
> > 
> I assume you've run tunefs -J enable on the filesystems on
> the journalled provider? Or used newfs with -J if it's a new
> filesystem?
> 
> If I remember correctly it's this flag that fsck checks to see
> whether fsck is needed or not.
> 
> You can check whether the flag is set or not by running dumpfs
> on the filesystem. Under "flags" it'll say gjournal if the
> flag is set.

I've just taken the file system off-line and run tunefs -J
enable on it, and tunefs said:
tunefs: gjournal remains unchanged as enabled
so I seem to have set it up properly in the first place.

In the "further reading" list on the gjournal article, there is
mention of mounting with async,gjournal options, but I see no
reference to gjournal in the man pages, so my guess is that this
is what has been superceded by the -J tunefs/newfs flag?

Cheers,

-- 
Andrew