Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Got myself into a tricky situation. Have aufs mounted at /mnt/1

aufs on /mnt/1 type aufs (rw,relatime,si=daab1cec23213eea)

I can't unmount the thing:

sudo umount -f /mnt/1
umount2: Stale NFS file handle
umount: /mnt/1: Stale NFS file handle
umount2: Stale NFS file handle
umount2: Stale NFS file handle

How do I unmount the mount point? (without rebooting the system)

(Note: aufs is on top of an openafs system rather than NFS.)

share|improve this question
Got into a similar situation, and could reproduce it easily: just remove the rw branch of the AUFS filesystem, and boom, the AUFS mountpoint is completely hosed. umount -f or umount -l won't change a thing. I'm still looking for a solution as well. – jpetazzo Oct 20 '12 at 1:24

from man 8 umount:

   -f     Force   unmount   (in  case  of  an  unreachable  NFS  system).
          (Requires kernel 2.1.116 or later.)

   -l     Lazy unmount. Detach the filesystem from the filesystem hierar-
          chy  now,  and cleanup all references to the filesystem as soon
          as it is not busy anymore.  (Requires kernel 2.4.11 or  later.)

If sudo umount -f /mnt/1 does not work, you can try sudo umount -l /mnt/1.

share|improve this answer
-l may take some time, right? Is there some additional option if -f doesn't work? – Ehtesh Choudhury Apr 19 '13 at 9:48

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.