I recently received the following question from a relatively new Mac convert:
“Does Time Machine back up to a physical disc or is it to back up to the .mac account?”
Great question!
For those in a hurry …
The official (Apple supported) answer is that Time Machine will not back up to a .Mac account, but will back up to any FireWire or USB external drive directly connected to your Mac. Until the recently, drives connected over a wireless network were not supported either (the introduction of Time Capsule changes this).
For those who are not familiar with Time Machine, check out my previous post for a brief overview.
For those more curious …
Apple's decision not to allow Time Machine to backup to a .Mac account makes sense. Firstly, unless you purchased a pretty hefty disk upgrade with your .Mac account, you wouldn’t have enough space to back up your whole drive. Secondly, the initial full backup would well and truly overrun the monthly limit on most internet accounts (at least here in Australia). Not to mention that backing up over the Internet would be mighty slow.
The decision not to allow drives connected over a wireless network makes less sense. Yes, the initial backup of the whole drive would take many hours (overnight is probably the only real option in this case). But after that, the network load would not be significant. And given the popularity of the Airport Extreme Base Station, I am sure there is a sizeable installed base that has exactly this configuration.
Given that the recently announced Time Capsule is effectively an Airport Extreme Base Station with an inbuilt large capacity hard drive, one could be excused for suspecting that Apple was simply protecting its future market position. After all, Time Capsule had not made it to market when Lepoard was released. And if Mac users bought a third party USB hard drive, connected it to their Airport Extreme Base Station and hooked it up to time Machine, there would be less demand for Time Capsule on its release.
We will probably never know the true reason behind the move to ignore wirelessly connected drives originally. What I do know is that the Time Capsule looks like a fantastic solution and I am eager to get my hands on one.
For the more technically minded …
For those of you who already have a wirelessly connected hard drive and want to use it with Time Machine, simply type the following command in a Terminal window:
defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1
Next time you go to the Time Machine preferences, you should see a complete list of all your connected volumes (drives) available and ready to use.
Note: As you can probably guess from the key name, Apple does not officially support this solution (although the fact that the key exists suggests some level of support).
I have not personally tried this (I do not have a wirelessly connected network drive), so I can not vouch for the results. I would be interested to hear from anyone who tries this.
written by Warren Denley