I've released the next version of my rZync test app. You can find a link to it here: http://www.clari.net/~wayne/new-protocol.html You should also snag the referenced librsync source, as some important bugfixes in librsync are needed to compile rzync. For those that don't know, rZync is my new-protocol test app that I'm using to try out some ideas on how to improve the rsync protocol. It transfers directory information incrementally, so it should have a much lower memory overhead than rsync. The most important change in this release is that I've replaced the name-cache code with something that will be more robust and should work great with really large file transfers. I also changed the command- line syntax and have it now parse several new options, such as -r, -p, -t and such (i.e. the previous behavior of -a being hard-wired to "on" is no longer present) and a few other things. Another important bug fix closes a neglected file handle so we don't overflow the open file limit. ** Be sure to use the new "rs" controlling script and not the old one. ** I've tried the code out on a fairly large data set (~4000 files in ~500 directories), but nothing close to some of you million-file folks. I would not yet recommend trying rZync in a production environment, but if you can run some large file-count tests, please let me know how things go. ..wayne..