This is a proof of concept for a backup solution that gives a full copy of a bootable OS X drive on a SD Card. A high capacity SD card can be added to your colocated Mac mini without costing anything more in terms of rack space fees. An external hard drive takes up space and costs you more money each month. We took a 4x speed 32GB SD card which goes for approximately $50. This SD card will work on any new Mac mini (Aluminum). If you are just using your Mac mini as a web server you very well might not even be using 32GB of space. A base install of OS X Server is between 6-7GB alone, and that can be trimmed down if needed. The following steps show how to reformat the SD card as a bootable Mac file system, use Carbon Copy Cloner to clone your hard drive to the SD card, and then we’ll boot off the SD card to verify the backup. Once we verify our backup we’ll boot off a OS X DVD and use disk utility to reformat the hard drive and copy the SD card contents back over to the hard drive.
Once you pop in the SD card go to Applications -> Utilities -> Disk Utility to properly format the SD card to be a bootable HFS+ volume. Click on the SD card on the left (the device, not the volume), then use the Partition tab to reformat it. Use the screen shot as your guide:
Be sure to click “Options” and choose GUID Partition Table so that our backup volume is bootable.
Now we can download and install Carbon Copy Cloner and setup a clone backup. Use the “Save Task” button to re-run the clone every night or weekend. Use the “Clone” button to start the first clone backup. On a standard install of OS X Server to this 4x speed 32GB SD card it took 2-3 hours for the first clone backup to finish. Every subsequent backup will just save the differences in the files and take considerably less time.
Booting the mini off the SD card does take awhile, but is possible. After reformatting the hard drive to simulate a drive failure, the Disk Utility off the OS X Server DVD was able to perform a recovery of the SD Card to the hard drive in less than 10 minutes. Rebooting off the hard drive brought the machine back to life like nothing ever happened.
Note: While this backup method might work for you, having multiple forms of backups is recommended. Backing up important files and databases to something like Amazon S3 would be a great way to prevent data loss.