Stefano was not really meaning litteraly every day for the pre-backup event, i am pretty sure he was meaning every time you run a backup!
So you do not have to worry on how to plan it, it will run automaticly anyway BEFORE, the actual backup start.. The only thing i am worry about is the actual time it could take to delete the backup...
My suggestion of rsync was rather to avoid to deal with a backup of the backup on a usb disk before deleteting it from the nas to put another backup...
If you are worry by the size Available for a new archive of backup, then you should considere a new strategy :
- buy bigger disks for your nas, or
- use rsync to avoid to have to deal with a complete set of copy of all the file and the need for twice the space for the backup. Rsync will simply update the old backup in place.