At last meeting of Security Treff Graz I brought up the question whether rsync is capable of handling extended ACLs (the Access Control Lists you handle with setfacl and getfacl on your Linux system). That’s very important for me when backing up running systems because I’m using ACLs on some systems but only a few programs (like star) are aware of the ACLs. So I took a closer look at it and the answer whether rsync supports extended ACLs is: "depends".
Out of the box rsync does not handle extended ACLs. But: there is a patch available (patches/acls.diff in upstream-sources) which provides support for ACLs via option ‘-A’. The best news: Debian uses the patch by default now starting with rsync 2.6.9-1 so we have ACL support within rsync on upcoming Debian/etch as well. This is very important because the nonstandard option only works if the remote rsync also supports it.