Rsync bug
Bitten by the rsync bug? I was. Apparently in the new RHEL 5.7, and I am sure the RH clones like CentOS, Scientific Linux and ClearOS(?) as well, there is a bug in rsync when you use it with ssh transport like so:
rsync -avz -e ssh remotehost:/data /data
The fix is to make sure to append a username to your host and then it magically starts working properly again.
rsync -avz -e ssh username@remotehost:/data /data
Enjoy!