I then got a ton of useful information on redirecting where BackupPC stores it's backup file pool from this article (moving the BackupPC pool to a new hardrive). I installed, formatted, mounted the new drive as /media/1TB and created a directory called /media/1TB/backuppc. I used the process:
- stopping BackupPC (sudo /etc/init.d/backuppc stop)
- copying the backup pool (sudo cp -dpR /var/lib/backuppc/. /media/1TB/backuppc/)
- renaming the current pool (sudo mv /var/lib/backuppc/ /var/lib/backuppc.orig)
- creating a symbolic link from the old location to the new drive (sudo ln -s /media/1TB/backuppc/ /var/lib/backuppc)
- starting BackupPC (sudo /etc/init.d/backuppc start)
- and when I was sure it was all working well - deleting the old backup pool (sudo rm -RI /var/lib/backuppc.orig)
The biggest suprise was the 4 hours it took to copy the pool too the new hardrive and the 1 hour it took to remove the old pool once I was sure everything was working correctly. Overall the process was scary, but happened without incident. Now I've got at least a few years of file proliferation before it becomes a problem again.