I use backup plugin with scheduled backup jobs (running every 2 days).
There is an option Keep (with description "Keep the last x days of backups"). I have is set to 5, but doesn't seems like old backups are deleted. At the moment I have 7 backups and the oldest is from the 17th of Feb. The only non-standard thing is a different path and additional sub-directory for backups added in /etc/default/openmediavault and it looks like that:
which saves a backup to /backups/omvbackup/ and sub-directory with a current date and hour.
Could anyone explain how to set it up to keep only last few backups please?