[CentOS] how to unmount an NFS share when the NFS server is unavailable?

Wed Jan 26 14:34:17 UTC 2011
Rudi Ahlers <Rudi at SoftDux.com>

On Wed, Jan 26, 2011 at 4:10 PM, Paul Heinlein <heinlein at madboa.com> wrote:
> On Wed, 26 Jan 2011, Les Mikesell wrote:
>>> That won't really work. The NFS clients run cPanel and we need a
>>> way for end-users to have full access to their backups all the
>>> time. We used to run backup over FTP, but then when a client wanted
>>> to restore data one of the techs first had to download it from the
>>> backup server and then let the client restore it. So I'm trying to
>>> cut down on unnecessary support tasks.
>> I don't see why the automounter wouldn't work for this, but you can
>> mount with the soft,bg options to keep from hanging.
> You need to be completely sure that 100% of your apps know how to
> handle I/O errors before using soft mounts.
> Errors in hard-mounted NFS filesystems will produce hanging
> applications, which are admittedly a pain, but the apps will stop
> issuing i/o calls until the filesystem returns. An app can never be
> fooled into think a write or read operation succeeded when it didn't.
> Soft-mounted filesystems, however, return error codes that
> applications can (and most often do) ignore, resulting in all sorts
> file corruption.
> --
> Paul Heinlein <> heinlein at madboa.com <> http://www.madboa.com/
> _______________________________________________

the problem I'm getting is that the NFS mount is for backups only, so
if it's off-line then no backups can be made, which I can live with
for the time being while it's being brought online again.

But, the problem I sit with is that other regular operations on the
local disk "hang" so to say, untill I manually unmount the NFS mount.
How do I get local operations to continue while the NFS mount if
faulty, but not unmounted?

Kind Regards
Rudi Ahlers

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