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I have two external drives I use for Time Machine backups. On each drive, I have Time Machine backups for multiple computers. My primary computer has a large disk, and the associated external Time Machine drive recently warned that it was getting low on space. I would like to migrate the profiles from all other computers off of this drive and on to the other external drive. How can I do this?

The key difference between my problem and other questions is that I don't want to just move the whole Time Machine volume to another drive. I want to just move some profiles. Ideally, they would migrate to the pre-existing other volume. I'm ok if I have to create a separate partition, but that would be second best.

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3 Answers

up vote 1 down vote accepted

You can move a whole drive using Disk Utility using block copy and it comes free with your Mac. You could then delete the profiles you don't want from your drives. This method doesn't move a single profile, though. You can't just do a straight copy because the 'hard links' are copied over as whole files rather than just links.

How To Move OS X Time Machine Backups To A New Disk.

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+1 for the "'hard links' are copied over as whole files rather than just links", though in 10.6 maybe that's no longer true, given Apple's own instructions at support.apple.com/kb/HT1427 As for the hard links, see also TimeCopy at code.google.com/p/timedog/wiki/UsingTimecopy –  Arjan Feb 25 '10 at 13:07
Fair enough, I think your answer is better than mine as it relates to 10.6 and I have upvoted you. –  alimack Feb 25 '10 at 15:24
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For 10.6 Snow Leopard, see the section "Mac OS X v10.6: How to transfer your back ups from your current hard drive to a new hard drive" in Apple's "Mac 101: Time Machine".

This is basically ensuring "Ignore ownership on this volume" is not enabled, and then dragging the folder "Backups.backupd" to the new hard drive. It seems to me one can do that for just the "profiles" one likes to move (or just copy the whole "Backups.backupd", and afterwards remove the subfolders for the computers one does not want), and leave the others on the current drive:

If you upgrade to a new hard drive with a larger capacity, you may want to transfer your existing Time Machine backups to it before using it for regular backups. To keep your existing backups on your new, larger backup hard drive, follow these steps:

  1. Connect your new hard drive.
  2. In Disk Utility, make sure it has a GUID partition and is formatted as Mac OS Extended (Journaled). If needed, reformat the drive as Mac OS Extended with a GUID partition. If you do not know how, see the steps in this article. Note: Back up any data on the hard drive before you format it.
  3. Select the new drive's icon on the desktop and choose Get Info from the File menu.
  4. Make sure "Ignore ownership on this volume" is not enabled.
  5. Open Time Machine preferences in System Preferences.
  6. Slide the Time Machine switch to Off.
  7. In Finder, double-click the current backup hard drive to open its Finder window.
  8. Drag the folder "Backups.backupd" to the new hard drive.
  9. Enter an administrator user name and password, then click OK to start the copying process. This may take some time to complete because all your backups will be copied.
  10. In Time Machine System Preferences click "Select Disk…"
  11. Select your new hard drive, then click "Use for Backup."

Now, on your new hard drive, you will have all of your existing backups from the previous backup hard drive plus have more room for more new backups.

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(Ensure to read the note on hard links in alimack's answer at superuser.com/questions/112007/migrating-time-machine-volumes/…) –  Arjan Feb 25 '10 at 13:09
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The answer is quite annoying... Normally you can't duplicate the contents, but there are a few utilities that can...

Off the top of my head, use SuperDuper! to clone the entire drive to the new one. But you can't selectively move a "single profile".

But first, take a look, how far back do your backups go on each system? Do you really need to move them to a different drive? Remember, Time Machine, will prune itself pseudo-intelligently. My Time Machine backup goes back to 4-9-2009.... I'm letting it prune itself as needed.

How big is your current Time Machine drive?

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