Re: Archiving content of a directory on a DVD-R.

["Thomas Schmitt" <scdbackup@gmx.net>]

Hi,

peter@easthope.ca wrote:
> Drive type   : vendor 'SONY' product 'CD-RW CRX320E' revision 'NYK2'

Ouch. That's a "Combo" drive which can write only CD-R and CD-RW.
With DVD media it can only do reading.

So there is no use buying writable DVDs for it.


> To squeeze the data, add -zisofs.

This can help if the data are compressible by a factor 3.
But that would be quite boring data.


>  xorriso -for_backup -dev /dev/sr0 \
>          -update_r . / \
>          -zisofs \
>          -commit \

Command -zisofs sets parameters for the compression. It needs an argument
or else it would eat the command -commit and complain that it is not
a suitable parameter for -zisofs.

To cause the files to be compressed you have to equip them by zisofs
filters. For best and slowest compression choose zlib level 9:

  xorriso -for_backup -dev /dev/sr0 \
          -update_r . / \
          -zisofs level=9 \
          -find / -type f -pending_data -exec set_filter --zisofs -- \
          -commit \
          ...

----------------------------------------------------------------------

> Likely xorriso provides a way to spread an archive over multiple CDs.
> Documentation or example?

That would be the job of an older project of mine:
  http://scdbackup.sourceforge.net/main_eng.html
  http://scdbackup.sourceforge.net/scdbackup-0.9.2.tar.gz

Installation and configuration are some work:
  http://scdbackup.sourceforge.net/examples.html#configure

(That's a reason why it is not in Debian. Another reason is that scdbackup
gets installed by particular users, which is good for isolating their
backup data but not suitable for the sysadmin-driven model of a Linux
distro.)

For building the software you need the C compiler and its companions
from Debian package "build-essential". Compilation happens automatically
during the run of ./CONFIGURE_CD or ./CONFIGURE_DVD.

After the installation you may simply run

  scdbackup_home

See
  http://scdbackup.sourceforge.net/examples.html#scdbackup_home

The more general command

  scdbackup

takes pathspecs as known from mkisofs and exclusions of paths:

  scdbackup /home /home2=/usr/home -not /home/guest

This example backups /home and /usr/home . It gives on CD the name /home2
to the directory tree that is /usr/home on hard disk. Subdir /home/guest
will not get into the backup.

(Back in 1999 a 650 MB CD-R was a respectable backup medium, competing
with 500 MB QIC tapes and 1.2 GB DDS tapes.
Nowadays i use them only for small backups and for software delivery.
My bread-and-butter backup media are now "25 GB" BD-RE media. They are
not much more expensive than DVD+RW. Only the prices of burner drives
are significantly higher for BD than for DVD.)


Have a nice day :)

Thomas