I checked my GFS backup jobs in the repository, and there are too many restore points. I set it to keep 12 monthly restore points, some of them are keeping over 20!
It seems to be from when I enabled the "Read the entire restore point from source backup instead of synthesizing it from increments" option. It kept all months up to that point, then the filenames changed and it's keep all the monthlies since then as well.
What do I do, I only want to keep 12 months as I configured it?