We've set up a Linux server to act as an NFS server for FireWire disk drives. After we're finished using a drive and we try to unmount (umount) it from the server, we get "device busy". We can get the filesystem to unmount by doing "service nfs stop" and "service nfs start", but this is not viable if we have other NFS exported filesystems in use at the time. Is there a way to get NFS to "release" a filesystem so it can be unmounted without having to stop the whole NFS service?

BTW, we've tried "umount -l" (lasy unmount) but it tends to cause other applications running on the server to hang.

You can unexport the filesystem on the fly with the exportfs command. For example:

exportfs -u host:/some/shared/path

Thanks for the response. It didn't work. But you pointed me in the right direction. I discovered that doing an "exportfs -f" allows me to unmount the filesystem.