on 10:23 Wed 26 Jan, Rudi Ahlers (Rudi@xxxxxxxxxxx) wrote:
> Hi All,
>
> How do I unmount an NFS share when the NFS server is unaivalable?
>
> I tried "umount /bck" but it "hangs" indefinitely
> "umount -f /bck" tells me the mount if busy and I can't unmount it:
>
> root@saturn:[~]$ umount -f /bck
> umount2: Device or resource busy
> umount: /bck: device is busy
> umount2: Device or resource busy
> umount: /bck: device is busy
>
> This non-working NFS share is causing problems on the server and I
> need to unmount it until such a time when the NFS server (faulty NAS)
> is repaired.
The specific solution is 'umount -fl <dir|device>'.
The general solution's a little stickier.
I'd suggest the automount route as well (you're only open to NFS issues
while the filesystem is mounted), but you then have to maintain
automount maps and run the risk of issues with the automounter (I've
seen large production environments in which the OOM killer would
arbitrarily select processes to kill ....).
Monitoring of client and server NFS processes helps. If it's the filer
heads which are failing, and need warrants it, look into HA failover
options.
Soft mounts as mentioned won't hange processes, but may result in data
loss. This is most critical in database operations (where atomicity is
assumed and generally assured by the DBMS). If the issue is one of
re-running a backup job, and you can get a clear failure, risk would be
generally mitigated.
--
Dr. Ed Morbius
Chief Scientist
Krell Power Systems Unlimited
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