"Last week, I told you about my NAS purchase, and my desire to explore desktop applications for backing up your Ubuntu computer. From the administrative interface of my Buffalo NAS, I created a network share that I could access with the different systems in my office. It's an SMB share so that it can also be accessed from Windows if needs arise. I then permanently mount those shares as network file systems (though not NFS) on my Kubuntu Karmic system. This I do from the command line
In general terms, DeltaCopy is an open source, fast incremental backup program. Let's say you have to backup one file that is 500 MB every night. A normal file copy would copy the entire file even if a few bytes have changed. DeltaCopy, on the other hand, would only copy the part of file that has actually been modified. This reduces the data transfer to just a small fraction of 500 MB saving time and network bandwidth. In technical terms, DeltaCopy is a "Windows Friendly" wrapper around the Rsync program, currently maintained by Wayne Davison. "rsync" is primarily designed for Unix/Linux/BSD systems. Although ports are available for Windows, they typically require downloading Cygwin libraries and manual configuration.
Unison is a file-synchronization tool for Unix and Windows. It allows two replicas of a collection of files and directories to be stored on different hosts (or different disks on the same host), modified separately, and then brought up to date by propagating the changes in each replica to the other.