Time Machine - Missing Data?

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Level 2

171 points

Time Machine - Missing Data?

Hi and thanks for reading,

just for curiosity I tried the first steps to migrate my Time Machine to my mac (I did a backup 5 minutes ago and trying to see how to use migration assistant).

By following all the steps and selecting everything from my Time Machine Backup, after the required space calculation I get a value of 105GB of total space required.

Now, by getting the informations of my Mac HD, I see that it contains 135GB.

The question is: what are these 30GB difference about? They cannot be all allocated for my operating system...

Thank you.

MacBook Pro, Mac OS X (10.6.7)

Posted on Jul 2, 2011 10:00 AM

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Answer 1

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William-Boyd-Jr

Level 6

10,578 points

Jul 4, 2011 12:43 PM in response to Jet787

Time Machine doesn't back up everything, only what's needed to restore your Mac. At least some of that unaccounted space is consumed by things like page and swap files, log files, cache files, etc.

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Answer 2

Jet787 Author

Level 2

171 points

Jul 4, 2011 12:49 PM in response to William-Boyd-Jr

Thanks, but if I only need 40GB less than the present space occupied on my MAC, why have I to keep these extra files?

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Answer 3

Jul 4, 2011 1:04 PM in response to Jet787

As far as the files that I mentioned, your Mac won't run without them. They'll be recreated on your Mac as it runs. That's why Time Machine doesn't back them up.

If you really want to learn where the space is on your Mac, launch the Terminal utility and enter this command:

sudo du -d 1 -h -x /

You'll be prompted for your administrative password. Enter it (you won't see anything), then press <return>. In the resulting display you'll see one line for each "top-level" item, either file or folder, along with the amount of space it consumes. The last line with show a summary for the entire drive.

One other thing you might have that might be large but isn't backed up is the file /private/var/vm/sleepimage . On my Mac its size is 4 GB.

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