If you are unable to unmount or lvremove a logical volume, verify that there are no processes holding the LV.
Locate the major/minor numbers for the logical volume you’re trying to remove (ie lvol0):
dmsetup info -c | grep lvol0
Take note of the 5th column, which indicates if a volume is “open,” and the 2nd and 3rd columns, which are the major and minor IDs, respectively. For example:
[root@eclipse ~]# dmsetup info -c | grep lvol5 datavg-lvol5 253 24 L--w 1 1 0 LVM-4WlscxDDEw5R9IvjgZYpu5FQeW9h835ADtQzXFr3cJ6SHEcgS4NFMxzaSKjUkedy datavg-lvol5-cow 253 27 L--w 1 2 0 LVM-4WlscxDDEw5R9IvjgZYpu5FQeW9h835ADtQzXFr3cJ6SHEcgS4NFMxzaSKjUkedy-cow
Find any process attached to this volume by searching on the major and minor IDs discovered above:
lsof | grep "major,minor"
[root@eclipse ~]# lsof | grep "253,24" beremote 14524 root 15r BLK 253,24 1835186 /tmp/filehRrCD8 (deleted)
Shut down or kill any process still accessing the volume to continue unmounting and removal.
If no processes show as accessing the volume in lsof, check to make sure nothing is sharing the filesystem (i.e. rsync, nfs, or samba).
If you have verified that no processes are holding the LV open, verify that the LV is not mounted somewhere:
If the volume appears in the output, unmount it using the umount command.taken from: http://kb.eclipseinc.com/kb/why-cant-i-remove-a-linux-logical-volume/