Bootable backup over the network?

[etanter]

Hi,

(I've just had to do a full system restore from a bootable backup, and it worked perfectly! thanks for this great software!)

I have seen in the user's guide that one can make a bootable backup only on a wired (USB/Firewire) drive, not on a network drive. This seems to be because backing up on a network drive results in a sparse image, which is not bootable.

I would like to understand why this is so, in particular, why is it not possible to make a bootable backup to a network drive.
Is this an inherent technical limitation of how remote copying works?

or maybe I'm just plain wrong in my understanding of the user guide, and one can in fact have SD do a bootable backup over the air?

Thanks,

-- Éric

[dnanian]

It's a technical limitation. When you're working with a network volume, you're working with a totally different file system - basically, a virtualized copy. You can't fully preserve all the information you need to preserve, and can't authorize sufficiently -- without an agent running on the far side -- to even write "system" owned files.

This is why both SuperDuper! and Time Machine use images as 'containers' - those images act like local drives, so we can preserve what we need to. But they can't be booted from - because they're not real drives.

[etanter]

Thanks, that clarifies the matter. Although it would be really cool to have a workaround to this, so as to be able to have a bootable backup without having to plug anything...

-- Éric

[dnanian]

Not likely to happen, Éric -- at least not without extensive OS X support for that kind of thing. (NetBoot, which works with OS X server, is something else entirely.)

[awm]

I just downloaded SD today for evaluation, and was hoping to be able to create a bootable copy via the network (planning to get an AE base station soon).

I planned to create the inital backup to a locally attached USB drive, then hook that drive to the network for incremental updates.
After coming across this post, I sadly realize this probably won't work, even with HFS+/Journaled formatted drives and over AFP (right?).

May I suggest a feature then (couldn't find anything like that in the docs or in the forum): How about the ability to create a bootable mini system on the same drive that's able to (1) boot the Mac when plugged in directly, (2) mount the image and (3) restore all the files?

I realize this could probably be done via booting from the original CD/DVD, but I find that procedure highly annoying (esp. searching for those CDs/DVDs).

[dnanian]

Well, you can partition the drive and install a basic installation of OSX on that drive, or do so to a memory stick...

Also, see the "Airport Disks" post at the Shirt Pocket blog for a discussion of the best way to do the local backup...