Is it a bad idea to use it for other stuff? I'd like to use it as a secondary Photoshop scratch disk. It will definitely get used, because my primary scratch disk is a 8gb flash drive.

I do have an external volume that I could use, but the internal drive is MUCH faster.

BTW, Time Machine rocks. I'd been using Quicksilver for years on this machine, and Time Machine is just so much more easy.

Hmm... a quick and unscientific experiment shows that the new internal volume is way faster than the flash drive too. So now I really want to use it.

You can use the TM volume for anything you want. I wonder if when it's backing up and/or writing to the drive if you'll notice a slowdown in the scratch disk function though. It's only once an hour, but if you're making a lot of changes to a lot of big files in that hour span it may take a while for TM to copy the files over.

One other thing to consider is once the TM drive starts filling up your scratch disk space will shrink. Once the drive fills up TM will delete the oldest backups to make room, but it only clears a few G off at a time, so you may end up with a fragmented scratch disk that's only 5 G or something.

You may want to read up a bit on how to save space in your TM backup. Such as having working folder/s that you exclude from TM, then you move the finished project from there when done. There's a lot of variables such as what size TM drive you have, the size of files you work on, how many files you modify daily etc.

That's just a quick rundown, got to run out for the day probably.

You could partition the drive so you have dedicated scratch space, no?

Yes.

I'll add that it can be partitioned, that will help keep enough free for scratch, but it still may slow up the scratch disk a bit when TM is backing up as it is physically the same drive.

For the time being, this should be fine. I just went from two 250gb drives to two 1tb drives, so I've got PLENTY of breathing room. If needs be, I'll replace these with a couple of 2tb drives in a few months. But that seems unlikely.

You can also edit the back up times so that it doesn't back up when you would be on the machine.
http://timesoftware.free.fr/timemachineeditor/

That looks very useful, but do you trust it? It seems kind of scary to just turn Time Machine off.

I would like it if Time Machine would only backup at night. Like once a night would be fine. Once an hour is too much, as I learned this morning when I was moving around about forty GB of photos and had Time Machine fire up and start copying them. I didn't need it to do that. Silly.

What typo did I make that got censored? I meant to type "Like at night."