Backup Time capsule content for later restore

From Apple Support Knowledge Base...

Time Capsule, Mac OS X v10.6.3 or later: How to transfer your back up from an existing Time Capsule to a new one

For this process, you should leave your computer in the same room as the Time Capsules, or use one Ethernet cable to connect your Mac to the Ethernet port on the existing Time Capsule, then use another Ethernet cable to connect from the existing Time Capsule to the new Time Capsule.

1. Configure your Time Capsule for your network. See the documentation that came with your Time Capsule for information about setting it up on your network.
2. Open Time Machine preferences in System Preferences.
3. Slide the Time Machine switch to Off.
4. Open a Finder window.
5. Locate both Time Capsules listed in the SHARED section of the navigation pane on the left of the Finder window. Note: If you do not see your Time Capsules in that section, choose Preferences from the Finder menu and make sure "Connected servers" is checked under SHARED.
6. Select the name of the new Time Capsule in the navigation pane. The default name is "Time Capsule xxxxxx", with xxxxxx being the last digits of the ID printed on the bottom of the Time Capsule.
7. Mount the volume by double-clicking the name of the volume in the Finder window's main section. The default drive name is "Data".
8. Open a new Finder window by pressing Command-N, or by choosing File > New Finder Window.

9. Repeat the previous 2 steps with the other Time Capsule, to mount it. Drag your backup disk image from the current Time Capsule to the new Time Capsule. This can take some time to complete because your entire backup will be copied.

10. Open Time Machine preferences in System Preferences.

11. Click "Select Disk...", then select your new Time Capsule.
12. Perform a Time Machine back up.
13. After the back up, you can remove the Ethernet cables if desired and configure your wireless network to your liking.

Can I copy those .sparsebundle files to an external hard disk and expect them to work as Time Machine backup resources again?

Almost certainly yes.

Modes and ownership

Ideally, use chmod(1) and chown(8) to have the mode and ownership, of the copy of the disk image, consistent with how Mountain Lion normally creates a local disk image for Time Machine.

Example

GPES3E-gjp4-1:~ gjp22$ sudo ls -al /Volumes/tall/com.apple.backupd/GPES3E-gjp4-1.sparsebundle/
Password:
total 16672
drwx------@ 3 root   staff     10  7 Jun 19:07 .
drwxr-xr-x  8 gjp22  staff     10  6 Jun 18:57 ..
-rw-r--r--  1 root   staff    500  7 Jun 18:03 Info.bckup
-rw-r--r--  1 root   staff    500  7 Jun 18:03 Info.plist
drwx------  2 root   staff  78855  7 Jun 19:07 bands
-rw-r--r--  1 root   staff    444  7 Jun 18:02 com.apple.TimeMachine.MachineID.bckup
-rw-r--r--  1 root   staff    444  7 Jun 18:02 com.apple.TimeMachine.MachineID.plist
-rw-r--r--  1 root   staff   1473  6 Jun 21:28 com.apple.TimeMachine.Results.plist
-rw-r--r--  1 root   staff  10698  6 Jun 22:24 com.apple.TimeMachine.SnapshotHistory.plist
-rwx------  1 root   staff      0 19 Mar 19:36 token

– and for each band, you should have:

-rw-------  1 root  staff 

Attaching the copy of the disk image

With Terminal, for the example above:

sudo hdiutil attach -readonly /Volumes/tall/com.apple.backupd/GPES3E-gjp4-1.sparsebundle/

If you use Terminal from within Recovery OS: you'll probably not need the sudo prefix to the command.

Additional detail

… whether I can still restore …

You require:

• a copy of a Time Machine destination, a copy that will be good for restoration
• not an additional Time Machine destination.

Assumption

You wish the copy to be usable, for restoration only, in the event of loss or failure of the Time Capsule.

If the disk is attached from a local image where modes and ownership vary from the norm for a local image:

• OS X or Recovery OS might use that disk without difficulty; I can't be certain.

Thoughts

If you're preparing for the possibility of loss or failure of a Time Capsule – and restoration from a copy of what was there – then think a step further, to backing up without the original Time Capsule. (If you wish the copy to be writeable by Time Machine, that could be a separate question.)

All things considered

It's probably quicker and simpler to use the external hard disk, or a part, as a Time Machine destination.