I got the above error when I was trying to re-run the rsback task that I previously killed its schedule backup process. I had issue with the server being backup so I had to terminate the process.
This error shows up and prevents the backup task from running because the lock file is still present, which indicats that a process could still be running. In order to fix this you need to remove the lock file and re-run the backup task. Look at your rsback config (/etc/rsback/rsback.conf) to find out the location of your rsback lock files, default is ”lock_dir = /var/lock/subsys”. In there you will see rsback lock files as ”rsback.backup_task_name.lock”, and just delete that file.
For those who doesn’t know or heard of rsback below is a short description from sourceforge.
rsback makes rotating backups using the common rsync program combined with hard-link copies on Unix-based backup hosts. This results in a fast and disk space saving backup technique.