Symptoms

Online migration of a ploop container fails with an error :

can not undump CT#1952305 : /usr/sbin/vzctl exited with code 152

The following errors can be found in /var/log/messages on the destination node :

Aug 18 13:15:23 bnt-node41 kernel: [165386.798310] EXT4-fs (ploop55455p1): recovery complete
Aug 18 13:15:23 bnt-node41 kernel: [165386.798322] EXT4-fs (ploop55455p1): mounted filesystem with ordered data mode. Opts:
Aug 18 13:15:23 bnt-node41 kernel: [165386.805435] PFCache: relink 182:887281 to "/vz/pfcache" +0 -0 =0 peers
Aug 18 13:15:23 bnt-node41 kernel: [165386.805472] EXT4-fs (ploop55455p1): Couldn't remount RDWR because of unprocessed orphan inode list.  Please umount/remount instead
Aug 18 13:15:23 bnt-node41 vzmdest[929387]: vzctl : Failed to mount image /vz/private/1952305: Can't mount file system dev=/dev/ploop55455p1 target=/vz/root/1952305: Invalid argument

Cause

Online migration fails because of file system errors inside the container.

Resolution

Restart the container.

If restart does not help, perform a file system check manually on the container's ploop image.