Hello.
We are using a backup procedure based on a combination of LVM snapshots and rsync.
In particular, the procedure is the following:
...
mysql -h
-u -p -e "FLUSH TABLES WITH READ LOCK; \! lvcreate -L -s -n "
...
At the end, we change the working directory, unmount and lvremove .
Sometimes, randomly, the umount command works but the lvremove fails and we are left with the lvm snapshot unmounted but we are unable to remove it.
We tried to force a removal without success with the following error:
Logical volume contains a filesystem in use
We didn't find any process using that device using lsof and we can't find any handler keeping the device busy.
Even a mariadb restart doesn't fix it and the only solution is to reboot the server.
The only thing we noticed is a message upon the snapshot creation:
File descriptor 4 (socket:[201844800]) leaked on lvcreate invocation. Parent PID 1564033: mysql
We know that this is the mysql unix socket.
Have you ever had such an issue?
Thanks a lot.
Kind regards.
Riccardo