Recently, I have started backing up my servers to Amazon S3 (Simple Storage Service) using Duplicity. So far, I am pleased with the process and the costs involved. I still do regular disk dumps to my own backup server but may slowly phase down the frequency of these dumps.
What is Amazon S3?
Amazon S3 provides a simple web services interface that can be used to store and retrieve any amount of data, at any time, from anywhere on the web. It gives any developer access to the same highly scalable, reliable, fast, inexpensive data storage infrastructure that Amazon uses to run its own global network of web sites. The service aims to maximize benefits of scale and to pass those benefits on to developers.
What is Duplicity?
Duplicity backs up directories by producing encrypted tar-format volumes and uploading them to a remote or local file server. Because duplicity uses librsync, the incremental archives are space efficient and only record the parts of files that have changed since the last backup. Because duplicity uses GnuPG to encrypt and/or sign these archives, they will be safe from spying and/or modification by the server.