Leaving out security concerns, which is the most bandwidth-efficient use of rsync for long-distance WAN transfers: rsh/ssh or modules?
I understand that modules assume no encryption by default, but everything I've read suggests that the CPU overhead for rsh/ssh is negligible on modern systems (e.g. multi Xenons), and the pipe won't back up with <1Gbs network speeds. I know that there is additional overhead with the rsh having to originate the remote shell and execute rsync, but given the amount of data, this seems negligible.
It would be a heck of a lot easier to just open up rsh and use rsync this way for this implementation, rather than set up a module for every server, but if the difference is measurable, I will of course do it with modules. Anyone have experience/opinions?