I thought I'd do a quick survey and figure out what backup tools are readily available in Ubuntu. I found 17 that might be worth mentioning. Many are front-ends, and front-ends-to-the-front-ends, so to keep them straight I cooked up a quick diagram with GraphViz:
So there's a lot, and I may have missed a few nodes or edges. So far, my favorite is probably mrb:
Package: mrb Description: Manage incremental data snapshots with make
rsync mrb is a single, self-documenting, executable makefile, which aims to make trivial the task of maintaining a set of compact, incremental, rsync mirrors of your important (and sometimes rapidly changing) data. . It relies only on the time-hardened industry tools GNU make and rsync. Snapshots may be taken at any opportune interval. Multiple snapshot targets can be configured in a modular fashion, so fast changing data can be separated from static bulk data, with snapshots of each scheduled or triggered on demand, as may be appropriate for each.
At first you think, "Perfect, how hard can a make frontend to rsync be?" 15 kilobytes of Makefile later, you realize this may not be as brilliant as it sounds on paper. But it is well commented and relatively user friendly, which may actually impede the code's readability (as if anything involving whitespace syntax could be readable). Such gems as:
# If I have to explain this one, then I guess you are just reading this # 'for the articles' -- but I hope you'll have enjoyed it anyway...
I haven't tried mrb yet, but I might put it on the TODO list. But first, I'll need to give jwz's method a full vetting.