Check your Time Machine settings

Are you using Time Machine to back up your Mac? You should check and make sure you're not backing up your Second Life cache folder. There's no reason to back it up, and it can waste a lot of space on your backup drive. I deleted the backups of my cache folder and got back about 50 GB of space.

Here's what you need to do to erase and exclude your cache folder:

1. Stop Time Machine by opening its preferences and clicking the big slider to OFF. Cleaning out your old backups will take time and we don't want TM starting up in the middle of it.

2. If you don't have the Action menu in your Finder window toolbar, add it by right-clicking in the toolbar, select Customize Toolbar, and drag the Action popdown onto your toolbar (it's the one with a gear on it).

3. Navigate to your SL cache folder. From your home directory, it's in Library/Application Support/Second Life.

4. Enter Time Machine by clicking its dock icon.

5. Select the cache folder, then go to the Action menu and select "Delete all backups of 'cache'"

6. This could take a long time (several hours) depending on how much crap you've got there. You can exit out of TM (hit the big Cancel button) and let it run in the background.

7. When that's done, go back to TM Preferences, click Options, then add the cache folder to the Do not back up list either by dragging it there or clicking the + button and navigating to it.

8. Now you can turn TM back on.

Thank you!

I just set up a Time Machine drive this weekend, and your suggestion makes a LOT of sense! (By the same logic, the cache location for your web browser could also be excluded from backups...)

I'll have to change those settings tonight!

You should also exclude ~/Library/Caches and /Library/Caches which are the folders that programs _should_ be using for their cache files. Most programs do, SL doesn't =)

For me this excludes 371gb of data from my back-ups. I have a 2.7tb back-up drive, but nearly 400gb is still a lot of unnecessary data!

I think that Time Machine by default excludes ~/Library/Caches. I don't have that folder explicitly excluded, but it's not backing it up either.

Maybe we should file this as a bug.

By the way, is it possible to tell Time Machine to use more than one external drive for storage? It looks like, if you have a 500 GB drive and manage to fill it up, it starts discarding the older change data. But the instructions for adding a new drive sound generally like "disconnect the old Time Machine drive, put it on the shelf, and start a fresh one.". Is that how it works? Or can I keep adding drive capacity so I have still got the ability to search back to the start-up state?

I don't think Time Machine can do that directly, but Mac OS X has a built-in generic ability to group a bunch of disks together in a striping or concatenated configuration. Then they look like one big disk, and you could tell Time Machine to use that disk.

But I don't think you really want to do that. If you combine disks in a RAID without redundancy, then when any of the smaller disks fail, your whole RAID goes. You're multiplying errors. Disks are cheap, you're better off just buying a new, bigger one.

I've got my external drives (two 1.5tb ones) striped together as a back-up for my four 750gb internal ones (which are also striped together). I like the speed increase for opening huge files, and I figure both RAID devices aren't very likely to die at the same time, anything that takes them both out would like leave a truly redundant set-up in ruins anyway =)