The 500GB disk in my first-gen Time Capsule became hopelessly full, with two Macs backing up to it and a slew of other media files stored on there to boot. Poking around on teh Google turned up some good tutorials on the mechanics of actually replacing the drive, particularly this one. Doing so is a pretty straightforward process for anybody who has ever cracked open a computer.

However, this Time Capsule has loads of data on it that I wanted to preserve, preferably in a quick-and-easy fashion, and I didn’t find much information on how to go about performing such a migration. It turns out to be not too difficult, but I made a few time-consuming missteps on the way. Hence my gift to you: everything you need to know to do it yourself.

First, a note on the drive

Without doing much research, simply thinking that quadrupling my capacity was a good goal, I picked up one of these drives, a WDC 2TB drive with EARS technology. I then found this comment, among others, that indicated Time Capsule might not support these drives, at least not without some jumpering.

I’m happy to report that my first-gen Time Capsule (running firmware 7.5.2) has had no issue dealing with that drive straight out of the box.

Partitioning

The Time Capsule requires a specific partitioning scheme to work. On my first attempt, I put the new drive in an enclosure, plugged it into my Mac, and gave it a single HFS+ partition using Disk Utility. When I put it into the Time Capsule, the disk was recognized but AirPort Utility reported a ‘problem’ with the disk. At that point using the ‘Erase’ button in AirPort Utility caused it to partition it in the required fashion. Doing that is the easiest and surest way to create the right disk structure, but it does require swapping the Time Capsule disks a couple of times before the process is complete.

It might be possible to create the required partitioning scheme manually prior to putting the drive into the Time Capsule, to avoid a swap. I’d be interested to hear from anybody who tries, to know if it’s practical. Here is what Time Capsule put on the disk (as discovered through Disk Utility after I took the drive out of the Time Capsule again and put it back in the USB enclosure):

• At the start of the drive, a partition named APconfig, type ‘Mac OS Extended (Journaled)’, size 1.07 GB (1,073,741,824 Bytes, to be exact). This partition had a single non-hidden file in it, apparently a backup of some of the AirPort configuration data.
• Immediately following, a partition named APswap, type ‘Mac OS Extended (Journaled)’, also of size 1.07 GB (1,073,741,824 Bytes, to be exact). This partition had no non-hidden files in it.
• Finally, a partition filling the remaining space on the drive, named the same as the Time Capsule was named (via the AirPort utility). This partition was also of type ‘Mac OS Extended (Journaled)’.

The third partition is the only one visible to the user after the drive is in the Time Capsule, and contains backups/other user data.

Archiving data

My main goal was to migrate the data from the old Time Capsule disk to the new disk. Happily, AirPort Utility has a handy ‘Archive’ button that will help you do just that. It will only copy data to a USB-attached hard drive, so you’ll require a USB drive enclosure to perform the migration. To start the migration:

1. Put the new, partitioned drive into a USB enclosure.
2. Plug the USB enclosure into the Time Capsule.
3. In AirPort Utility, go to the ‘Disks’ pane.
4. Click the ‘Archive’ button.
5. Select the third, large partition on the new disk as the target.
6. Start the archiving process.

Copying my 460GB of data took a number of hours, so it’s best to be able to leave it overnight.

Once the archival is complete, you’ll need to do a bit of fiddling with the file structure to make the data usable by the Time Capsule. The archival process will put the entire contents of the main disk partition into a folder called “<Time Capsule name> Archive” (or something to that effect). Underneath that, I had a folder named ‘Shared’, which contained the shared-folder Time Capsule data. Since I have configured my Time Capsule to use user accounts, there was also a ‘Users’ folder, with another folder for each account inside of that.

These ‘Shared’ and ‘Users’ folders need to be in the root directory of the disk for them to be usable by the Time Capsule. So, you’ll need to:

1. Plug the USB enclosure into your Mac
2. Open the drive corresponding to the third, large partition on the disk
3. This partition should contain a single folder, ‘<Time Capsule name> Archive’. Move the contents of this folder into the root folder of the drive, then delete the (now-empty) ‘Archive’ folder

Once this is done, the drive will be usable in the Time Capsule, and all of your old data will be accessible. Swap disks in the Time Capsule as discussed in the tutorial listed above, and off you go!