So, last night, TN ground to a halt because of a failure in the backup system. Yay, I have backups. Boo, the drive they’re on died, thus failing to mount, and the backups went, due to a quirk of my backup system, to the HD with the root of the filesystem. Filled that up quickly, it did.
So, resolved. No backups for now, not until I pick up a new TB drive.