[Linux-cluster] Re: [NFS] [RFC] NLM lock failover admin interface
James Yarbrough
jmy at lolita.engr.sgi.com
Tue Jun 13 15:23:44 UTC 2006
> There seems to be an unstated assumption here that there is one
> virtual IP per exported filesystem. Is that true?
This is the normal case for such HA services. There may actually be
a single IP address covering multiple filesystems and/or NFS exports.
> I think that maybe the right thing to do is *not* drop the locks on a
> particular filesystem, but to drop the locks made to a particular
> virtual IP.
For filesystems such as ext2 or xfs, you unmount the filesystem on the
current server and mount it on the new server when doing a failover.
In this case, you have to be able to get rid of all the locks first and
you do that for the entire filesystem. For a cluster filesystem such as
cxfs, you don't actually unmount the filesystem, so you really need the
per-IP address approach.
> If I want to force-unmount a filesystem, I need to unexport it, and I
> need to kill all the locks. Currently you can only remove locks from
> all filesystems, which might not be ideal.
This is definitely less than ideal. This will force notification and
reclaim for all exported filesystems. This can be a significant problem.
jmy at sgi.com
650 933 3124
Why is there a snake in my Coke?
More information about the Linux-cluster
mailing list