On Friday 04 June 2010, Dejan Muhamedagic wrote:
> Hi Takatoshi-san,
> 
> On Fri, Jun 04, 2010 at 02:19:42PM +0900, Takatoshi MATSUO wrote:
> > Hello
> >
> > I suggest to add a parameter which decides executing fsck
> > as user's policy in Filesystem RA.
> >
> > Because, current RA dose not check ext3 because executing fsck depends on
> > filesystem.
> > But ext3 sometimes is broken and remounted read-only although it has
> > journal, so
> 
> Under which circumstances does this happen?

No filesystem is perfect ;) And any kind of hardware issue can cause 
filesystem and data corruption. 

Takatoshi-san, you should notice however, that for example e2fsck will start 
to run in non-auto mode, even if only a journal recovery is required. With 
default extX paramters, it then easily might perform a complete filesystem 
check, which might last hours. Not only that you might get unexpected long 
down time, you also need to be aware, that fsck time is often MUCH longer than 
the resource start timeout. If that happens, pacemaker will kill fsck in the 
middle of a run, which might damage your filesystem even more.

That is all fine if you know about possible consequences, but I really doubt 
that most admins are aware of that.

> 
> > I want to decide myself executing fsck before mount to operate more
> > safely.
> >
> > This new parameter has three mode "auto","force" and "no".
> > Default is "auto" which do the same thing as before.
> > "force" and "no" mean what they say.
> 
> Patch applied. Many thanks!

That brings up and idea here, with extX, we could easily use 

dumpe2fs -h | grep "Filesystem state:" 

to check if fsck needs to be run. So the agent could refuse to mount the 
decide and make you run it manually in the foreground without any timeouts...
I will implement that for our lustre_server agent (a heavily modified 
Filesystem agent) and then possibly back-port the patch.


Cheers,
Bernd

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