I might be a bit oldfashioned, but I prefer to use my onw backup solution on my NAS rather than relying on a tool by the supplier.
I use two external Harddrives, which I exchange in intervals. To backup my content on it, I use good old rsync.
Note that for this approach to work, you should turn on the "User-Home-Service", otherwise, there is no home directory for admin.
To install the script, ssh to the NAS with the admin user: ssh admin@yoursyno.domain
Then change to root using sudo -i.
The backupscript is simple. Note that it just creates an archive on the disk.
Since my target disk currently is on NTFS, I use raw rsync. At a later stage, I will change to rsnapshot. (Which requires you to install perl on the NAS first.)
Without further ado, here is my script:
I added this in /etc/crontab to start the backup daily. Note how I use the flock command to ensure that only a single instance of the backup is running. It is important to put the lockfile in a location other than /tmp.
Finally, I need to make sure that the logs do not overflow. To that end, I created this file in /etc/logrotate.d