I have read that it is possible to 'umount' a disk that is otherwise busy by using the 'lazy' option. The manpage has this to say about it:
umount - unmount file systems
-l Lazy unmount. Detach the filesystem from the filesystem hierarchy now, and cleanup all references to the filesystem as soon as it is not busy anymore. This option allows a "busy" filesystem to be unmounted. (Requires kernel 2.4.11 or later.)
But what would be the point in that? I considered why we dismount partitions at all:
- To remove the hardware
- To perform operations on the filesystem that would be unsafe to do while mounted
In either of these cases, all a 'lazy' unmount serves IMHO is to make it more difficult to determine if the disk really is dismounted and you can actually proceed with these actions. The only application for
umount -l seems to be for inexperienced users to 'feel' like they've achieved something they haven't.
Why would you use a lazy unmount?