Using rsync with extended attributes
The command rsync is like a network aware copy program, and it is designed to replicate every part of the original file (ownership, group membership, etc.). It also transfers only the portions of the file that are necessary - so a slight change in a file on one host means a minimal network transfer to the other host.
However, rsync has had problems preserving extended attributes such as the Finder data and resource forks from MacOS X. Kyle Crawford has done an excellent write-up on the state of MacOS X extended attributes support in rsync 3.0.0-pre7 (a prerelease of 3.0), and it looks like the problems with rsync may be over. This is indeed good news. He used a tool called backup-bouncer to verify the MacOS X metadata; this tool looks very useful.
Kyle also has an excellent entry on his attempts to use rsync on MacOS X up to that point.
The traditional way to get all of this data on MacOS X was to use the ditto command line utility, but rsync now seems to be improving to where ditto may not be necessary (or perhaps it is…).
The rsync 3.0.0-pre7 release (as well as the current rsync-2.6.9 release) is available for download at the rsync download page. There are also important security advisories for rsync daemons in versions 2.6.6 and older; upgrade to the latest release version (2.6.9).
3 comments 7 January 2008
