CompTIA Linux+ XK0-006 (V8) Practice Question

The -l (or --lazy) option performs a lazy unmount. It removes the filesystem from the namespace right away so system shutdown or other administration can continue, but defers the actual release of resources until the kernel sees that no process is still using the mount. This is the option specifically recommended for unresponsive or unreachable network filesystems that would otherwise cause umount to block.

• -f forces an unmount, but it can still block on some operations and may corrupt data if writes are pending.
• -R recursively unmounts a hierarchy of mount points and does not address the busy-mount problem.
• -n skips updating /etc/mtab but does not help when the filesystem is busy.

Therefore, the lazy unmount flag (-l) is the correct choice.