Force unmount of NFS-mounted directory

Question

I have an NFS-mounted directory on a Linux machine that has hung  I ve tried to force an unmount  but it doesn t seem to work     umount -f  mnt data   umount2  Device or resource busy   umount   mnt data  device is busy   If I type  mount   it appears that the directory is no longer mounted  but it hangs if I do  ls  mnt data   and if I try to remove the mountpoint  I get     rmdir  mnt data rmdir   mnt data  Device or resource busy   Is there anything I can do other than reboot the machine

User · Accepted Answer

You might try a lazy unmount   umount -l

User · Answer

Your NFS server disappeared   Ideally your best bet is if the NFS server comes back   If not  the  umount -f  should have done the trick  It doesn t ALWAYS work  but it often will   If you happen to know what processes are USING the NFS filesystem  you could try killing those processes and then maybe an unmount would work   Finally  I d guess you need to reboot   Also  DON T soft-mount your NFS drives   You use hard-mounts to guarantee that they worked   That s necessary if you re doing writes

User · Answer

I had the same problem  and  neither           umount  path -f  neither           umount nfs  path -f  neither           fuser -km  path  works  finally I found a simple solution    lt   sudo  etc init d nfs-common restart  then lets do the simple umount  -

User · Answer

If the NFS server disappeared and you can t get it back online  one trick that I use is to add an alias to the interface with the IP of the NFS server  in this example  192 0 2 55     Linux  The command for that is something roughly like   ifconfig eth0 fakenfs 192 0 2 55 netmask 255 255 255 255   Where 192 0 2 55 is the IP of the NFS server that went away   You should then be able to ping the address  and you should also be able to unmount the filesystem  use unmount -f    You should then destroy the aliased interface so you no longer route traffic to the old NFS server to yourself with   ifconfig eth0 fakenfs down   FreeBSD and similar operating systems  The command would be something like   ifconfig em0 alias 192 0 2 55 netmask 255 255 255 255   And then to remove it   ifconfig em0 delete 192 0 2 55   man ifconfig 8  for more

User · Answer

Try running  lsof   grep  mnt data   That should list any process that is accessing  mnt data that would prevent it from being unmounted

User · Answer

Couldn t find a working answer here  but on linux you can run  umount nfs4  volume -f  and it definitely unmounts it

[linux] Force unmount of NFS-mounted directory

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