One that's not mentioned, that I found quite useful, is http://github.com/astrails/safe

Yes, I also found astrails-safe quite useful. I've written up a four-part blog post about backing up your website using Amazon S3 and astrails-safe: http://techiferous.com/2009/11/getting-started-with-amazon-s...

indeed astrails safe (http://astrails.com/astrails-safe) is missing :) and it is the most popular on ruby-toolbox: http://ruby-toolbox.com/categories/backups.html

it can dump:

* mysql

* postgres

* filesystem

* subversion

storage:

* local

* sftp

* s3

* rackspace cloudfiles

extra:

* backups can be encrypted with gpg

* backups can be rotated

oh, and all this is configured with a very simple ruby dsl!

We've been using astrails in production for 10 month now and are quite satisfied with it so far.