[Duplicity-talk] archive format (Replace tar?)

[Rob Braun]

I may have mentioned this some time ago (1yr+?), but the web page
(http://www.nongnu.org/duplicity/new_format.html) talks about a
new file format that would be more suitable for duplicity.  I'd
like to bring attention to the xar project 
(http://www.opendarwin.org/projects/xar/) which addresses many 
of the concerns raised on the duplicity page.  xar provides
a header which contains all the indexing information for the
archive.  Once the header is read and parsed, extracting an
arbitrary file or attribute from the archive is as simple as
seeking to it and extracting it.  Each file in the archive
is compressed individually, avoiding the tar.gz problem of
needing to decompress the entire archive before extracting
what you need from it.  xar also supports adding arbitrary
metadata to the archive.  This would make it possible for
duplicity to extend the archive to support any extra features
it needs.  xar handles ACLs and EAs on Linux, FreeBSD,
and Mac OS X.  It also handles resource forks and ._ files
on Mac OS X.

If any of the developers here would like more information or
assistance with xar, I'd be happy to answer any questions
you might have.

Rob