Using Time Machine with a Time Capsule

Q3.  Can I use my Time Capsule for backups AND other data?

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You can put other data on your Time Capsule's internal HD, but there are three major considerations:

  1. Especially for things like photos and videos, access may be too slow for convenient viewing, and worse for editing. So test this a bit before you decide what to put there.

  1. Time Machine cannot back-up that other data, so you'll need some other method. See question #Q6.

  1. Time Machine will, by design, fill up all the empty space available to it, so there may be a conflict between the sparse bundle disk image it puts your backups in, and the other data.   Since you can't partition the internal HD (short of physically removing it, placing it in an enclosure, partitioning it, then putting it back -- which voids the warranty), sooner or later you may run out of space unexpectedly.  

It is fine, though, to back up multiple Macs to the same Time Capsule (it was designed for that), but see Time Machine FAQ #33, especially the pink box there, for more info and some considerations.

Or, there is a workaround, to "reserve" some space there, by creating a disk image of the desired size and storing your data there, but it's rather cumbersome, and two Macs can't share it at the same time.

Here's how to reserve some space with a disk image (connect via Ethernet if possible):

  1. a.Start the Disk Utility app (in your Applications/Utilities folder). Click the New Image icon in the toolbar (or select File > New > Blank Disk Image from the menubar). If the little arrow to the right of the "Save As" box points down, click it so it points up.

  1. b.Give it a name in the "Save as" box. This name will appear on the Time Capsule's disk, with ".dmg" appended. (Similar to the way the sparse bundle containing your Time Machine backups appears, with ".sparsebundle" appended).

  1. c.Click your Time Capsule in the sidebar. It may take a few moments for Disk Utility to recognize it, and show it in the center pane.

  1. d.In that center pane, select the blue Share folder for your Time Capsule (you may need to scroll down, or enlarge the window, to see it). Once selected, you'll see any existing disk images in the right pane.

  1. e.Give the Partition a name. This name will appear on your desktop and/or Finder sidebar when you mount the .dmg by double-clicking it, if you have the External Disks box checked in Finder > Preferences > General  or  Finder > Preferences > Sidebar.

  1. f.Select the Size for the amount of space you want to reserve, either one of the pre-sets or Custom which allows any size. Avoid taking all the remaining space for the disk image, as Time Machine needs a bit of room to operate. Also note that if very little space is left, it will begin deleting old backups very soon, to make room for new ones.

  1. g.Select the desired Format, probably the default of Mac OS Extended (Journaled).

  1. h.If you want it encrypted, select the desired type.

  1. i.Select single partition, either GUID or Apple Partition Map.

  1. j.Select Read/Write disk image for Image Format.

  1. k.Click the Create button. The larger the image size, the longer this will take.

When complete, the new disk image will be automatically mounted on your Mac's desktop, ready to receive the files you want to move into it. (When you first open a disk image, there may not be a sidebar and/or toolbar; if so, select View > Show Toolbar from the Finder menubar.)

To access this disk image from another computer, you must first eject it from this one, since only one can mount it at a time. Otherwise, the other one will see a message that the disk image is "Temporarily unavailable."

Note that you may be able to change the size of this disk image later, via Images > Resize from the Disk Utility menubar (while the disk image is not mounted or selected in Disk Utility's sidebar). That will not work, however, with the sparse bundle that Time Machine uses.

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Another is to reduce the maximum size of the sparse bundle containing your backups. 

Note: this won't "stick" if you’re on 10.6.3 or 10.6.4.  Time Machine will automatically increase the maximum size to the size of the volume it’s on.

See the yellow box in Troubleshooting item #A8 for instructions.

One alternative is to connect a USB drive to your Time Capsule.  Then you can back up to the Time Capsule's disk and use the USB drive for other data, or vice-versa.  See question #Q2 for instructions. But note that Time Machine cannot back-up the USB drive while it's connected to the Time Capsule (see question #Q6).