[CentOS] how to unmount an NFS share when the NFS server is unavailable?
Les Mikesell
lesmikesell at gmail.com
Wed Jan 26 23:26:13 UTC 2011
On 1/26/2011 4:55 PM, Dr. Ed Morbius wrote:
>
> 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.
Actually, since the original question involved access to backups, I
should have given my usual answer which is that backuppc is the thing to
use for backups and it provides a web interface for restores (you pick
the historical version you want and either tell it to put it back to the
original host or you can download a tarball through the browser). Very
nice for self-serve access. It does want to map complete hosts to
owners that have permission to access them but with a little work you
make different areas of a shared system look like separate hosts.
--
Les Mikesell
lesmikesell at gmail.com
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