Reducing the space used by Time Machine's backups

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Level 1

20 points

Reducing the space used by Time Machine's backups

How do I make Time Machine use less space? How can I free up unwanted older backups?

The drive in question is not just used for Time Machine -- there is a Parallels VM on the drive as well, and the drive is now full. Parallels is complaining, and won't do anything else.

How can I force TM to free up some disk space?

Mac Mini 1.42 1G, Mac OS X (10.4.3)

Posted on Mar 9, 2008 6:57 PM

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Answer 1

adamb529

Level 4

1,163 points

Mar 9, 2008 7:01 PM in response to keybounce

In Time Machine, you can use the gears menu in the Finder toolbar to manually delete backups. You could partition your external hard drive and limit Time Machine's drive space too.

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Answer 2

Jeremy P

Level 3

740 points

Mar 9, 2008 8:25 PM in response to keybounce

It's not advisable to constrain Time Machine to much less than double the size of data being backed up. You can constrain Time Machine to retain fewer backups as Adam advised, delete some of your older backups then create a new partition to reduce the space available to Time Machine. If you need to reduce the size of backups you need to consider excluding items.

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Answer 3

keybounce Author

Level 1

20 points

Mar 10, 2008 9:39 AM in response to adamb529

The only thing I can find on the gear menu will let me delete the backups of a given file; I didn't see anything for trimming parts of the backup tree.

What I'd like to do is something along these lines:

1. Tell TM that "I have a target space remaining of X; delete enough surplus backups so that I will have my X available when you are done". Right now TM has an X hardcoded of 0; I'd like to have some space for other things.

Note that this is simple enough that it probably does everything I want.

2. Be able to run the "trim the backups" automatically. At least, by double clicking something on the dock. No new backups, just trim some old stuff.

Not quite everything I want, but pretty close.

3. Some way to tell what is safe to delete in the backup tree. Can I, for example, just nuke one or more of the directory trees safely? (Given that everything is hardlinks, I suspect the answer is yes, but I don't know for certain.)

4. Some way to tell what is actually taking up space in the backup tree. "**" is useless because the same file appears multiple times, and will be counted multiple times. In other words, how much will I save by deleting what files, what backup sets, etc.

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Answer 4

Jeremy P

Level 3

740 points

Mar 11, 2008 11:42 PM in response to keybounce

Not sure what you mean by the backup tree. The options in gear menu allow you to delete a file or folder, or all examples of that file or folder or a particular timed backup.

If you use the latter you could simply delete backups, oldest first, until you have the space you need. As for what is taking up space in your backups, it is essentially what's taking up space on your internal hard drive. If there's anything big there you don't need backed up you could exclude it from future backups and then delete all instances in your existing backups.

Once you've freed space on your backup drive you can constrain Time Machine to the smaller space by partitioning the drive to that size (or resizing your existing partition). X, in other words, is the partition size you allocate to Time Machine. It then does exactly what you want.

I'n not sure what you mean by "no new backups" but if you want to strictly control when Time Machine backs up, turn off the big switch in the preference pane and just order manual backups as required from the Dock or Menu bar.

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Answer 5

Mar 12, 2008 9:43 AM in response to keybounce

You could partition the drive so that TM uses one part and Parallels uses another. However, this would be static and the size couldn't adjust on the fly.

Good request, did you submit it to Apple as feedback?

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Answer 6

keybounce Author

Level 1

20 points

Mar 15, 2008 4:25 PM in response to Jeremy P

[quote] Not sure what you mean by the backup tree. The options in gear menu allow you to delete a file or folder, or all examples of that file or folder or a particular timed backup. [/quote]

I mean: All of the data from a given backup set

If I go into time machine, navigate to the external drive, and select the backup folder, the gear menu has an option to remove all copies of that. (I'm going from memory; I'm NOT going to try it again, for obvious reasons).

Doing so brings up a barber pole (horizontal), and wipes the drive.

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Answer 7

adamb529

Level 4

1,163 points

Mar 15, 2008 4:30 PM in response to keybounce

As it should. You removed all copies of the backup folder...so you wiped the drive.

What part of your question still needs to be answered? To delete all the data from a given backup set, open Time Machine. Make sure nothing is selected in the window. Using the dates on the right side of the screen (backup tree in this thread), select the oldest backup. Click the gears (Action menu) in the toolbar, and select Delete Backup. Does this make sense?

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Answer 8

keybounce Author

Level 1

20 points

Mar 17, 2008 10:51 PM in response to adamb529

I expected it to remove that one backup set.

At worse, it might remove all backup sets.

It should not remove stuff that has nothing to do with the backups that happen to be on the same drive.

It did. Said drive is now partitioned, and Time Machine has its own partition. But it still took out a parallels machine, and all of my client's "hidden" data/settings (everything in the registry, or in local settings -- application data, my documents, and desktop were backed up).

Meanwhile, now that I know the "better" way to do things, I won't run into this problem again. I hope.

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