On Wed, 09 Jul 2014 14:15:03 -0600 Nathan Shearer <mail@xxxxxxxxxxxxxxxx> wrote: > When I have an nfs share that is mounted with the hard option (either > explicitly or implicitly since hard is on by default), and the nfs > server becomes unresponsive for any reason, it often causes the entire > OS to hang on many operations. In some cases I cannot even reboot a > server depending on what the nfs share was used for. > > I relaize that this was probably done intentionally to prevent data > loss. However, when I am cleaning up a disaster and I actually do want > to "umount -f" a stalled nfs share and data loss es acceptable, then I > expect that command to return and the share to be unmounted. From a > usability perspective, stalling forever when I am explicitly forcing an > action is not right. > > There is a workaround: and that is to assign the IP of the nfs server to > my system then issue umount -f, however that hardly the best way since I > am changing my network topology to unmount an offline filesystem. In > some situations adding an IP to an interface is not possilble, and if > the system is a remote system it could lead to more problems since it is > mostly unresponsive. > > It would be greatly appreciated if a patch could be introduced that > allows "umount -f" to actually work without making any other changes to > a running system. The man page for umount even states that the -f > argument can be used to unmount an unreachable nfs share -- but it > almost never works. > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html Hi Nathan, you don't say what kernel you are running.... A change was made in Linux 3.12 (8033426e6bdb2690d302872ac1e1fadaec1a5581) which may address the problem you have. So if you are using a kernel older than that, try a newer kernel. This may not make "umount -f" work, but it should stop it from hanging. To make it work you might need to kill all the processes using the mount point first. Also, "umount -l" might be a suitable answer to your problems. NeilBrown
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