Nightly clean up - What logic does it use to remove backups?

Hi, we have a set value of Min 30 and Max 100 for file backups, does the nightly clean up leave it alone until it hits 100 or clean up until its down to 30?

I ask as i notice my server is just running the nightly clean up continually, and it seems to only list the minimum value, and is removing all backups until it hits this low value. If a server isnt backing up you end up with no back ups as maybe they were missed for a few weeks.

We have about 15-20Tb of backup, were doing hourly files, due to the above ive moved it to once every 24 hours and reduced the maximum until its finished the clean up (which looks like it will take at least a week), were trying to store about 30 days worth (at hourly that was about 500 backups which we felt wasnt huge, however it appears it is.

I cant seem to find the historic log of backup and nightly clean ups either, only shows about 20 on screen in activities.

We removed all soft limits to see if that was creating an issue. I am also wondering if (for what ever reason) it was not doing the nightly clean up… hence the need to see any historic logs.

We are unable to get to the backend of the server as its running directly on a QNAP NAS.