For those of you who use rdiff-backup, you may have run into the situation where the partition you’re backing up to has no more space available. This is a very annoying situation, because rdiff-backup needs space to be able to roll back the session, so you’re kind of stuck. You might think: “doesn’t a decent file system have a reserved amount of space for the super user?” Yes, decent file systems do, but you’ll often be running rdiff-backup as root, so that won’t do any good.
There is a very simple solution. So simple, you might not think of it, hence this post. Simply make a dummy file of, say, 50 MB on the target partition, which you can delete when you need the space for rolling back. To make such a file l33t-style:
dd if=/dev/zero of=/location/dummyfile bs=1048576 count=50