[CentOS] how to unmount an NFS share when the NFS server is unavailable?
Paul Heinlein
heinlein at madboa.com
Wed Jan 26 14:10:55 UTC 2011
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/
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