Editing VPS Management (section)

== Problems un-mounting - and with mount_null’s ==

If you cannot unmount a filesystem, beacuse it says the filesystem is busy, it is because of three things:

a) the jail is still running

b) you are actually in that directory, even though the jail is stopped

c) there are still dev, null_mount or linprocfs mount points mounted inside that directory.

d) when trying to umount null_mounts that are really long and you get an error like “No such file or directory”, it’s an OS bug where the dir is truncated. No known fix

e) there are still files open somewhere inside the dir. Use <tt>fstat | grep <cid></tt> to find the process that has files open

f) Starting with 6.x, the jail mechanism does a poor job of keeping track of processes running in a jail and if it thinks there are still procs running, it will refuse to umount the disk. If this is happening you should see a low number in the #REF column when you run jls. In this case you ''can'' safely <tt>umount –f</tt> the mount. 

Please note -if you forcibly unmount a (4.x) filesystem that has null_mounts
still mounted in it, the system '''will crash''' within 10-15 mins.