Connect a cheap little hard disk, tuck it out of the way, and just let your Mac clone to it daily. In our example scenario in the picture above, the disk is connected to the USB hub in an Apple Cinema Display, and kept out of sight in a TwelveSouth HiRise; this slows it down to USB 2.0 speeds, but that doesn’t really matter, in part because the clone happens at night, but also because after the initial backup, SuperDuper can update only those files that have changed.
If you have a PowerPC Mac and want to be able to boot from your clone, the disk you use for this has to connect using FireWire rather than USB (since PowerPC Macs can’t boot from USB).
Technically, you can also clone to a disk image on a network drive rather than to a local disk, but while this has merit in edge cases, it’s not usually the best option.
Good because: Creates perfect copy of your internal disk, which you can restore from, or, best of all, boot from in an emergency.
But be aware that: There’s no versioning, it can be slow depending on the interface, and there’s no protection against local disasters.
In picking an external disk to use with Time Machine or cloning (or even for use on a network), the temptation is to pick a cheap, simple hard disk, and though that’s fine, you can give yourself some extra protection by choosing a RAID disk.
RAID disks use two or more hard disks inside a single enclosure, and while they can be configured in increasingly complex ways the more disks they have inside them, for our purposes the key thing is that one of these ways is to mirror the contents of one of the internal drives to the other constantly, automatically.
When new data arrives, it’s written to both disks at the same time. This provides extra redundancy whether you’re backing up to it using Time Machine or a cloning app such as SuperDuper, so that even if your internal drive fails and even if one of the disks inside the RAID fails at the same time, you still have one good copy of your data. Backup is all about mitigating risk, and this is a classic way to do it.
The two disks just appear as a single disk as far as your Mac is concerned, so there’s no added complexity.
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