I just came across the fact that Rsync Version 3 is available for testing. I probably use rsync more than any other unix utility, and so I am very excited about some of the new features which include, to name a few:
I would also be curious to know the clever ways other people are using rsync. I have used it to do everything from synchronize directories to act as a software distribution system. It is also important to note that the license for Rsync is now GPLv3. The Samba team has made some very public statements about their support for GPLv3. This obviously limits the usage of rsync in proprietary software.
I wonder how -xattrs behaves. On the version of rsync that came with OS X 10.4 Tiger the -E option to preserve extended attributes meant that those attributes would be copied for every file every time, which seemed to slow down large backup operations quite a bit.
For me, a Japanese, the --iconv option is the biggest! I'd like to use this for daily backup from windows(shift-jis) machine to linux(utf-8).
Like R. Brown, I too wonder about the efficiency of rsync resource fork transfers. FWIW, I have been using the custom-patched rsync+hfsmode [ http://www.quesera.com/reynhout/misc/rsync+hfsmode/ ] because it only transfers resource forks when they've actually changed, and also doesn't require that the destination rsync daemon be patched (as the Darwin/Mac OS X 10.4+ version requires when syncing with non-Mac destinations).
I have been using rsync for years. An initial benefit rsync gave me back in my dial-up days, was repairing Linux CD images from sometimes broken CD's I'd get from a local Linux related shop. If ever I got a badly burned Linux distro, I would take an image of it with dd, and then over my 33.6k MODEM I would run rsync against it and the original downloadable image it was burned from. Then I would burn the fixed image to CD. Thankfully I can now download a CD in minutes. But I still use rsync for other things.
With computer virtualization, I can now replicate servers at different locations with little bandwidth transfer. A production system at an office location, can be transfered to a satellite office or the home of a staff member.
This can provide full off-site backup at either location, ready to boot without needing to restore, while allowing local access to current data. With some scripting, this can also provide off-line backup once the sync has finished. Of course this is suitable for situations where perhaps only one person needs access at their home or many at a satellite location. This could also be used in "follow-the-sun" type businesses, to minimize bandwidth use and maximize local performance.
At any one moment in time, you can typically have two current backups or one current and one only hours old. Off-site, off-line and safe. After the sync has finished, VM images can be committed to tape, for even greater safety.
rsync and virtulization. I love it.
How much does the licence change to GPLv3 really limits the usage ? rsync is not library and I don't think there might be some licence problems when you call application by exec ... is some analysis available somewhere ?