On Tue, 07 Oct 2008 20:18:53 PDT Antonius <antoniuso at gmail.com> wrote:
> I?ve fairly recently got my opensolaris home server running pretty near to
> exactly how I want it with a bit of help from some posts here. Now that
> that?s done I want to do a system level backup rather than piping out a bunch
> of config files and having to re-install and config again should the worst
> happen. All my data is stored separately on zfs raidz sets. The OS is
> installed on a 300GB IDE HDD. I think only approx 8GB are used. As it?s a
> home server there is no problem shutting it down, physically removing the
> system disk and placing in another system should it be required or anything
> like that.
>
> I?ve looked up a few potential solutions so far, but have yet to find one
> that sounds like it?s absolutely ?it?. What else is everyone else using?
>
> My priorities are basically as follows:
> Backup entire system so that it can be restored via a single process being
> kicked off
> Have some way of sensibly storing the image file (eg spanned across DVDs, a
> reasonably compressed file, etc.) that will allow for me to store a few spare
> copies.
> Being able to push the install to a smaller capacity faster hard disk (if
> possible)
> Lastly if an easy solution doesn?t exist to know how to best configure future
> builds to satisfy any requirements to achieve this.
I don't think you can get what you want. Basically, the problem is
that a full disk backup with one-command restore will only work for a
very small set of installations - those they are tailored for. Outside
of commercial OS's that always install the same boot manager and file
systems, there aren't enough of any one kind of installation to
justify the effort involved in releasing a product. Further, this
kind of thing just isn't that useful. Most people want a backup
solution that lets them do things like create incremental updates to
the backup, and retrieve individual files when someone accidentally
deletes them. If you're planning on backing up the data on your raidz,
you'll probably want those things, which means you'll need a second
backup utility for it. Is having a one-command full restore for the
system disk really worth dealing with a second backup
format/command/etc just for it?
The real issue with a full-disk backup is the boot manager. Those
aren't in the file system, but may have intimate knowledge of the file
system. Installing some of them involves poking the block numbers of
files in the file system into the boot loader blocks. So to handle a
boot manager properly, you either have to have intimate knowledge of
both the boot manager *and* the file system any further boot
information is on, or just do a block copy of every bit on the
disk. Even then, the easiest route to "restoring" the boot manager is
still to reinstall it after you've restored the disk.
Given those two problems, most backup software deals with backing up
file systems, and lets the user deal with the boot manager. Hence they
don't meet your requirements.
That leaves the various partition managers. None of them are likely to
understand zfs yet - it's arguably only available in preview and/or
experimental form - so you're only going to find tools that will
do block copies of the disk.
There are a lot of things that will do part of what you want. Without
knowing what you're willing to give up some part of your requirements,
or how willing you are to write some software on your own, and what
your requirements are for your *other* backups, it's not clear which
is appropriate.
> After that I?ll probably mirror the system disk too. I wasn?t thinking the
> current build would be good enough to move into production use so to speak.
That, on the other hand, is straightforward if the system disk is a a
zpool. Just use zpool attach to attach the second device. You'll have
to install the boot blocks on the second disk after setting up the
mirror if you want to boot from it.
<mike
--
Mike Meyer <mwm at mired.org> http://www.mired.org/consulting.html
Independent Network/Unix/Perforce consultant, email for more information.
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