Umounting a Busy Drive Revision as of Sunday, 20 December 2015 at 19:56 UTC
This is all too common:
umount: /media/backupdrive: device is busy
umount: /media/backupdrive: device is busy
Using lsof
You could try lsof to see what’s using the drive. Use the device name
(/dev/sd*) like so:
lsof | grep sdd
Using fuser
A more ‘proper’ approach is to use fuser:
[nikhil@example ~]# fuser -m /dev/sdd5
/dev/sdd5: 5138
So PID 5138 is using the drive. Let’s see what it is:
[nikhil@example ~]# ps aux | grep 5138
nikhil 5138 0.2 2.7 219212 56792 ? SLl Feb11 11:25 rsync -avh --exclude-from=/home/nikhil/manifest / /media/backupdrive
Aha! Now if you’re confident that you can kill that job, go ahead and
then try umounting the drive.