Update: Apple have finally added proper support for this!

Inspired by Jeff Atwood’s post a few weeks ago, last week I finally set up an offsite backup strategy. I picked up two 320gb Hard Drives + a firewire caddy for each (A$300 total, ouch) and am now rotating them to work weekly. One of the reasons I’m finally doing this is the ease of creating a bootable backup compared to doing it on Windows; and the other was that Time Machine makes general backups easy. Of course after I bought the second drive, I discovered that using Time Machine with multiple drives isn’t as easy as it could be.

There is absolutely nothing wrong with multiple drives, and Time Machine does support it – to the point where in 10.5.2 it will happily let you choose which TM drive to browse without first switching the target backup drive. But there’s a boatload of misinformation out on the net so I waited all week to post this and make sure my assumptions were correct. Apple has made a very robust backup solution. If you’re doing offsite backups it is not 100% automated, but that is a trade off for more flexibility.

I started with my two drives, and created an initial time machine backup on both. This gave me an immediate off-site backup rather than sitting on it for a week. I even ran a stress test – in the middle of the initial sync on the second drive I ejected it. Time machine stopped, and when I plugged the drive back in it did a quick scan then copied only what was left of the initial sync. Works perfectly.

Friday is my offsite swap day, so I arrived home this afternoon with my second drive and plugged it in. This is where time machine becomes a minor chore – you have to manually change the backup drive. Once that was done, it spent 5 minutes (according to the system log) comparing the 30gb main drive to the backup and then did a nice big 14gb copy (I migrated iTunes during the week). This proves my initial assumption that each individual drive will work exactly the same as if you had one backup drive and only plugged it in for one out of every two weeks; TM scans for old backups on the swapped drive with no complaints. If I need a file that was deleted while backing up onto the drive currently offsite, I can either wait until my next swap or plug it into one of the macs at work.

The final step in the process was creating a bootable backup. I know TM backups can be restored, and despite buying FireWire enclosures to allow PPC bootingI can’t even boot from these firewire drives on the iBook – but I’m definitely buying a mac mini in the next 3-6 months and at that point I want to have the option to instantly boot from the backup (which I’m doing nightly).

I know backup boot works after watching AJ boot from his Carbon Copy Cloner backup when he sent his laptop in for repair, but having analysed the feature sets and perceived reliability of the backups I forked out the cash for SuperDuper!. CCC certainly looks fine and has better scheduling options, but after trialling SuperDuper! it was just so much more obvious how to do a smart backup and it seems to have better support for backing up the currently booted partition.

One day I might even use it’s ability to create the bootable backup onto the Time Machine partition; but for now I have a backup of Mum’s data I need to store on that drive and it only supports ignoring the Time Machine folder, nothing else.

I’ll take a pic of frankenlaptop soon, but I’m waiting on a USB soundcard which will add to the plethora of USB devices it’s using and be the final key in my dual machine setup :D

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