Home Forums Mac Software Mac Operating Systems How to create bootable back-up disk for OS X Lion?

What I did was use SuperDuper to clone the InstallESD.dmg image onto my TM backup. (When SuperDuper makes a clone, it will carefully step around any TM backup on the destination volume, leaving it unscathed. The result is a single volume that is both a TM backup and a Lion Install disk.)

That makes your TM backup bootable. It doesn't boot into your latest (or indeed, any) snapshot. It boots into the Lion installer. One of the install options is to recover from a TM backup.

I took the time to test this thoroughly. It can install Lion onto a blank disk, and then use Migration Assistant to recover user files. Or it can restore any particular TM snapshot onto any volume, even a blank one. If the snapshot you restore from was from when you were running Snow Leopard, it (the Lion installer!) will happily reinstall that copy of Snow Leopard. If the snapshot you restore from was from when you were running Lion, and you're restoring onto a blank volume, it'll happily carve out and initialize a matching Recovery HD partition adjacent to that volume. (And, if you're restoring Snow Leopard to a partition that already has Lion on it, it'll reclaim that Recovery HD partition, reabsorbing it into the now-Snow Leopard partition.

In short, it just works, doing whatever you want in the way you would expect it to work.

Now, admittedly, if your main drive has died, you won't be able to restore onto it. You'll have to buy a new drive to replace the dead one, but that's just the way it is. You can't really fault Apple for that.

And, the fact that you still can't just boot from your backup disk and be up and running, without the delay of restoring onto a new disk, is also to be expected, if you think about it. A bootable clone is a useful kind of backup to have, but you'd be insane to rely on that as your only backup. The moment you actually boot off your only backup, you have no backup, and running without a backup is just crazy. Even if you have a bootable backup, the only thing you're going to do with it in an emergency is to immediately clone it again, and we're talking about the same delay as if you restored from any other kind of backup.


But of course, you wouldn't rely on only one method. You'd use #1 and #2 and #3 and:

Option #4: Internet Recovery. If your machine shipped with Lion, then it has in firmware sufficient recovery logic to establish an internet connection and net-boot off a recovery partition on one of Apple's servers. From there, you can install the latest version of Lion, even onto a completely blank disk. It'll even initialize the disk for you, in case it's not already GPT/HFS+(Journaled), and re-create the Recovery HD partition, so you won't have to use Internet Recovery every time.