On Friday 04 June 2010, Florian Haas wrote:
> On 06/04/2010 02:47 PM, Bernd Schubert wrote:
> >> Remind me of the VCS repo for that lustre_server agent please?
> >
> > Hrmm, I still didn't post it here. An older version is in the lustre
> > bugzilla:
> >
> > https://bugzilla.lustre.org/show_bug.cgi?id=20807
> >
> > I also attach it to this mail, the  "_to_be_tested" version has a better
> > if condition for the Lustre umount bug, but that part is really difficult
> > to test and I don't want to find out on customer system that I introduced
> > a typo somewhere...
> 
> Can you please explain your motivation for forking the Filesystem agent
> for something Lustre specific? I ask because others seem to have
> successfully deployed Lustre with an unmodified Filesystem RA.
> 
> http://wiki.lustre.org/index.php/Using_Pacemaker_with_Lustre

Yes I know this page and of course, the generic Filesystem RA also works. But 
IMHO

- The generic RA is complex, mostly due to support for OCFS2. For the Lustre 
RA I removed all of that complexity

- The Lustre RA is specifc to linux, as Lustre so far only runs on linux, I 
could remove further complexity. We might think this over, once Lustre works 
on Solaris as well.

- The Lustre RA provides more useful log messages, what it is presently doing 
and which step might have failed

- The Lustre RA tries to figure out external journal devices

- The Lustre RA knows about lustre umount bugs

- The Lustre  RA performs Lustre health checks to check if a LBUG came up


Of course, you can implement all of that into the generic RA as well. But all 
those Lustre specific options would need to be put into if-conditions, which 
increases complexity even more. And as I said before, extX (and so lustre 
lfiskfs as well) can be checked with dumpe2fs if fsck needs to be run. That 
will not work for any other filesystem type - again more complexity.

If I have the choice between duplicate and complex code, I prefer the 
duplicate choice....


Cheers,
Bernd


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