[H-GEN] DVD+RW media for backups

[Jason Parker-Burlingham]

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I've come into possession of a DVD+RW drive which is also capable of
writing CD-Rs and -RWs---pretty much the whole alphabet soup.  I've
been playing with it trying to come up with a cheap, simple and above
all reliable way to make backups of my system.

Obviously level 0 backups must be written to DVD.  There simply isn't
room on a CD, and there's barely room on a DVD even if I compress the
image.

Subsequent levels of backup could *probably* be written to a DVD with
growisofs (which allows you to conveniently add a file to an existing
ISO9660 disc) but so far I haven't been successful on that front[1].

I'd like to be able to script this---making backups by hand is made a
*little* easier with LVM and filesystem snapshots but sitting around
and nursing the process to completion is not going to be tenable in
the long run.

Oh, and before anyone mentions it, I can't recommend cdrw-taper (a
drop-in replacement of AMANDA's taper which allegedly supports writing
images to DVD+RW); for one thing I don't think the version as
distributed really supports DVD+RW, and for another I'm still very
unclear on how it's all supposed to work.  I'd rather write something
of my own and test it thoroughly over a period of months and years.

System information pertinent to making suggestions follows.

 $ df -k
 Filesystem           1K-blocks      Used Available Use% Mounted on
 /dev/hda1 [2]          5376940   3399640   1977300  64% /
 /dev/burling/var       5139776    856344   4283432  17% /var
 /dev/burling/home     20966720   5926004  15040716  29% /home

The system has only two users, is connected to the Internet through a
slow dialup connection, and has one 40GB disk.  (The 10GB or so you
see missing is as-yet-unallocated slack space which *could* be turned
into another LVM block device.)

I can continue to fill this message with more information, but I think
it's best to turn it over to the HUMBUG hivemind for now.

Any suggestions?

jason

[1] : I tried writing a several-gigabyte backup of / into a directory
      and making an ISO disc out of that, which was successful, but
      adding to it with growisofs's -M option wasn't successful---both
      backup images were truncated to only a couple megabytes each.

[2] : Note that the root filesystem isn't on an LVM device; this is
      because it would make the system inordinately difficult to
      boot.  It's a shame, because both /var and /home are able to be
      snapshotted to make it possible to get sane results from
      xfsdump(8).
-- 
Baby Pictures:
      http://panix.com/~jasonp?HenryGrosvenorParkerBurlingham

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