A Rift in the Space-Time Continuum

I did it. Yes, I finally did it: I went and pissed off Time Machine.

I've been using the Staff Backup drive for my Time Machine backups, see. And that drive needs a certain amount of free space for any large chunks of data that staff might create during any given day. So when Time Machine finally ate up all the disk space on the drive, I decided to see what would happen if I cleared some space up by hand, the old fashioned way. And so I deleted the first month's worth of data from my Time Machine backupdb folder.

Now, I'm not totally stupid, and I have at least a good enough understanding of how Time Machine works to know that this would cause problems, but I was curious, and I wanted to see what those problems would be and how they would manifest themselves.

The first thing I got was a generic Time Machine failure:

Time Machine Failure
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Clicking the red info button revealed surprising details, considering my drive showed 200GB free:

Time Machine Error: Really? How do You Figure?
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So I decided to run a backup and see what happened. The backup appeared to start smoothly, but eventually I wound up getting this message:

Time Machine Error: Funny Math
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Hmmm... I think I broke it.

It makes sense, really. I mean, it stands to reason that, in Time Machine, the first and oldest backup actually contains the most actual data. It's the base for all the other data. Subsequent backups only copy changes, but the first backup is kind of the Mother of All Backups, if you will. Deleting that first backup will, unsurprisingly, wreak all sort of havoc on your backups.

Havoc that is, as far as I can tell, irreversible. The only way I've found to fix this is to start the backups fresh. That is, turn off Time Machine, delete the old backups (or at least move the old backupdb folder out of the way), and then set Time Machine up again.


Oh well.

Ahhh! That's more like it.

Time Machine: Back Up and Running
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