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

Wed Jan 26 14:10:55 UTC 2011
Paul Heinlein <heinlein at madboa.com>

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/