Looking for multi-DVD spanning archiver

Robert G. (Doc) Savage dsavage at peaknet.net
Sun Jun 6 18:28:28 UTC 2010

On Sun, 2010-06-06 at 13:53 +0930, Tim wrote:
> On Sat, 2010-06-05 at 21:24 -0500, Robert G. (Doc) Savage wrote:
> > I want to be able to copy that directory with all its subordinate
> > directories, files, ownerships, permissions, etc. onto a minimum
> > number of DVDs. Ideally I'd want to pop all those discs into a DVD
> > drive on a new machine and use 'cp -a' to recreate the .../Everything
> > directory.
> A problem with trying to do /that/ simply is the differences between
> file systems on the hard drive and the DVD.  The file and directory
> permissions may change (typically, you'll find restored files and
> directories might be read-only, and files being executable, because
> that's how they were on the DVD, and the copying process keeps them the
> same), likewise for ownership (DVDs don't support different users and
> groups) and SELinux contexts.
> Generally, backups need to use some form of container that understands
> those things, and can restore them with the file.  The tarball being the
> traditional technique.

Two things to report. First, the discspan script also crashes after the
first DVD-R under F13. I'm so not a Python type, so this is going to
take me a while to figure out.

Second, the attribute differences between what discspan records on a
DVD-R and the original ext3 filesystem are trivial:

                    ext3            DVD-R
Ownership           doc:doc         doc:root
Directories         drwxr-xr-x      dr-xr-xr-x
Text files          -rw-r--r--      -r--r--r--
RPM files           -rw-r--r--      -r--r--r--
File/dir names         <exactly the same>
Dates/times            <exactly the same>
Sizes                  <exactly the same>
Duplicates          hard links      separate files
SELinux context           <don't care>

Bear in mind that all I'm trying to do is make a simple, reasonably
portable mirror of the Everything repo (for which there are no ISOs).
Its component files (mostly RPMs) total 59.7 GB (50 GB with hard links).
No amount of compression could yield a tarball that would fit even on a
25 GB BluRay disc, so spanning must be used to create a multiple-disc
set. The only question, then, is what algorithm to use before creating
each individual disc image in the set. discspan's simple sort approach
is very appealing.

Now all I have to do is fix it. :-)

--Doc Savage
  Fairview Heights, IL

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