Thanks Ann,

Doing multiple simultaneous backups is never intentional. There will be a process that does hourly backups in the background, and someone (unaware of that) might decide to do a manual backup to another location at the same time. I was considering disabling garbage collection in the automatic backup for that reason, to ensure that there would be no accidental simultaneous garbage collection. If it doesn't matter, I guess I'll leave it on to keep the database fresh, since the cost seems to be small.