Information Technology Reference
Figure 5: If you see this alert, you can turn on Time Machine with
Choose Local or Network Backups
The last step is to connect your drive to…what? If you're backing up
just one Mac, then obviously you'll connect it to that computer, and
you needn't ponder the matter further. But if you have more than one
Mac, you should consider whether you want to physically move the
drive between computers to back up each of them, or leave it attached
to just one of them and back up the other(s) over your network.
With a local backup, you plug your hard drive into one computer and
let your backup software run. (Time Machine starts automatically;
some other software requires either an explicit schedule, or that you
manually run backups after attaching a drive.) When it's done, you can
disconnect the drive and hook it up to another computer.
The biggest advantage of a local backup is speed . Even with a fast
network, chances are your backup will go much more quickly over a
FireWire, USB, eSATA, or Thunderbolt cable. Another advantage: any
backup software that can create a bootable duplicate can do so with
a locally attached drive. As far as I know, only Carbon Copy Cloner,
ChronoSync, Retrospect, and Synk can make bootable duplicates over
a network—though none of them can make bootable duplicates to a
Time Capsule (even if it has an external disk connected).