Hyper-V VM with a database failed to backup.
The VM is an Ubuntu virtual machines on Hyper-V.Binary log shows:
Information 2016/03/01 10:15:01 69 Data Plugin HYPERV VM [Ubuntu virtual]: Worker process has been assigned task with id
Job Message 2016/03/01 10:15:01 69 Data Plugin HYPERV VM [Ubuntu virtual]: Preparing working folder for backup
Job Message 2016/03/01 10:15:23 69 Data Plugin HYPERV VM [Ubuntu virtual]: Starting VSS snapshot creation
Error 2016/03/01 10:17:06 69 Data Plugin HYPERV Error creating VSS snapshot
Warning 2016/03/01 10:17:11 69 Data Plugin HYPERV VM [Ubuntu virtual]: Failed to create VSS snapshot; retrying
Error 2016/03/01 10:18:55 69 Data Plugin HYPERV Error creating VSS snapshot
Error 2016/03/01 10:18:55 69 Data Plugin HYPERV VM [Ubuntu virtual]: Failed to create VSS snapshot
Job Message 2016/03/01 10:18:55 69 Data Plugin HYPERV TaskID completed, backup failed
Error 2016/03/01 10:18:55 69 Data Plugin HYPERV VM [Ubuntu virtual]: Backup failed
Error 2016/03/01 10:18:55 69 Data Plugin HYPERV Worker process has exited prematurely