Forcibly Unmounting NFS Filesystems

forcibly unmounting nfs filesystems

available solutions

4. Use the fuser(1M) command with the “-k” option to kill the processes holding files

open in the target filesystem. (See important fuser(1M) syntax note below.)

5. Issue the umount(1M) command again to successfully unmount the NFS filesystem

now that all processes holding files open in the filesystem have been killed.

Figure 1 - fuser(1M) successfully killing processes holding an NFS filesystem busy

In the above example, fuser(1M) was able to correctly identify and kill the processes that

were holding the NFS filesystem busy, thus allowing the filesystem to be successfully

unmounted while the NFS server was down.

important note on fuser(1M) syntax with NFS filesystems

When using fuser(1M) to query NFS filesystems, always specify the target filesystem

using the format “server:/filesystem” as opposed to specifying client-side path where

the filesystem is mounted. For example, in the case of the following NFS filesystem:

Filesystem Mounted on

hpatcux6:/opt/netscape /nfs_mount

The target filesystem specified on the fuser(1M) command line should be

hpatcux6:/opt/netscape and not /nfs_mount.

fuser(1M) is able to recognize the server:/path syntax as being an NFS filesystem and

it makes no attempt to stat() the remote filesystem, which in the case of a down NFS

server would result in an fuser(1M) hang.