Howtoforge posted a tutorial about setting up Unison File Synchronization between two servers on Ubuntu 11.10
This tutorial shows how to set up file synchronization between two Ubuntu 11.10 servers with Unison. Unison is a file-synchronization tool similar to rsync, but the big difference is that it tracks/synchronizes changes in both directions, i.e., files changed on server1 will be replicated to server2 and vice versa.Setting Up Unison File Synchronization Between Two Servers On Ubuntu 11.10
I do not issue any guarantee that this will work for you!
