Skip site navigation (1)Skip section navigation (2)
Date:      Fri, 23 Jan 2009 02:40:01 +0100
From:      cpghost <cpghost@cordula.ws>
To:        Gary Kline <kline@thought.org>
Cc:        FreeBSD Mailing List <freebsd-questions@FreeBSD.ORG>
Subject:   Re: how to create a DVD backup filesystem?
Message-ID:  <20090123014001.GA2536@phenom.cordula.ws>
In-Reply-To: <20090123011043.GA86638@thought.org>
References:  <20090123011043.GA86638@thought.org>

Next in thread | Previous in thread | Raw E-Mail | Index | Archive | Help
On Thu, Jan 22, 2009 at 05:10:46PM -0800, Gary Kline wrote:
> 	Guys, I've got several directories off ~kline/ that I want to
> 	store permanently.  Like all my development code in ~/devel, and
> 	all my music mp3's and ogg's in ~/Music, and all my online and
> 	mp3 books from libribox.org in ~/readings.  There are PDF files
> 	and HTML and a slew of other stuff.
> 
> 	Can I use K3B or some other GUI program to create a filesystem on
> 	either a few CD's or one DVD?  Right now, I'm cross-backing up
> 	stuff to four live servers.  It's just data, but I would like to
> 	be able to inset it into my optical tray, cd to it and cd to
> 	wherever and read or listen to AND (if some disaster strikes) be
> 	able to copy my files from the disc to the computer.
> 
> 	I think I figured out how to create a tiny filesystem on a floppy
> 	disc, but this was a Long time ago.  Anything "push-button"?

Perhaps there is something like that, but I do it manually like this:

* mkdir cdr/
* copy approx 3.0 to 3.1 GB worth of files into cdr/
* mkisofs -R -J -o cdr.iso cdr/

Then use dvdisaster (/usr/ports/sysutils/dvdisaster) to
augment cdr.iso with RS02 error correction data. This creates
a bigger cdr.iso of 4.4GB ISO with approx 32% to 40% redundancy,
which is quite good.

Now, burn it to DVD:

* growisofs -dvd-compat -speed=8 /dev/cd0=cdr.iso

and make sure your system is as (disk-)idle as possible while
burning.

To use growisofs, install it from /usr/ports/sysutils/dvd+rw-tools.
You may need to

# kldload atapicam

so that you can get /dev/cd0. Don't forget that you need write
permission to /dev/cd0 and /dev/pass0, so either run growisofs
as root, or add this to /etc/devfs.rules:

perm    cd0     0666
perm    pass0   0666

and restart devfs (/etc/rc.d/devfs restart).

After having burned the DVD, eject it, and insert it again.  Then read
it back in with dvdisaster (to some OTHER directory!), and verify the
integrity of the backup (with dvdisaster). That's an important step,
as you can never be sure that the burning was flawless, unless you
were able to read it back in without faulty sectors.

If you plan to archive the DVDs, be sure to schedule some date in
a couple of years ahead to read them back in and verify their
condition. If some of those DVDs developed bad sectors, you could
then try to reconstruct those with dvdisaster (but only if you created
the error correction data before burning!), and burn a new DVD.

Oh, and try to stick to good DVD blanks like Taiyo Yuden or Verbatim
(only those made in Taiwan or Japan) to minimize the risk of bad
sectors (i.e. especially avoid no-names or el-cheapo blanks).

You can also do without dvdisaster, and write more than 3 GB to the
DVDs, but if you plan to archive them and be able to read them a few
years ahead, you'll highly value the error correction codes
overhead. ;) Oh, and you'll still have to read the data back after
burning, just to be sure everything's okay. Some kind of checksums
(md5, sha256) of the directories would be useful, so plan ahead
and add them before creating the ISO.

Note that all this is possibly already integrated in K3B or some
other fancy GUI front-ends, or it may not: I'm not familiar with
the GUI tools.

> 	tia,
> 
> 	gary

Regards,
-cpghost.

-- 
Cordula's Web. http://www.cordula.ws/



Want to link to this message? Use this URL: <http://docs.FreeBSD.org/cgi/mid.cgi?20090123014001.GA2536>