Presentations
These presentations go into detail about the background of the problem which this framework tries to solve.
openSUSE Knowledge Sharing, 2008
A talk held at the Novell/SUSE premises in July 2008. The slides are available as PDF here, and a video as ogg file (480 MB).
It includes some live demos, showing two metalink clients (aria2c and DownThemAll) in action.
ApacheCon EU 2008
The following is from a talk held at ApacheCon EU 08 about the MirrorBrain, called "Scaling Your Download Infrastructure With Your Success". Available as PDF: http://mirrorbrain.org/files/talks/apachecon08-mirrors.pdf
Abstract:When an organization offers files for download, and grows public, infrastructure might need to serve more requests than the single organization can technically handle. One option to scale is using paid services of a content delivery network (CDN). This is often not affordable, especially for Open Source projects. Another way is building up a mirror infrastructore. But choosing an appropriate mirror is often left to the user, and mirrors might be out of date, incomplete, or unreliable.
This talk shows how to build a poor man's CDN, using plain mirror servers and a redirecting Apache HTTP server. On the example of download.openSUSE.org, it shows how mirrored content can be transparently integrated into the web service, and how requests are redirected to geographically close mirrors using IP geolocation. The demonstrated infrastructure comprises means to scan mirrors and keeping track of present files in a MySQL database, active monitoring of mirrors, and mod_zrkadlo, a redirecting Apache module built upon the DBD framework.
Along the way, the talk discusses different approaches in geographical redirection of bulk data, load sharing with weighted randomization, high availibility and scaling issues, mirror stickiness, and client side robustness. Also discussed are problems that have been encountered in real life, solutions and open questions.
FOSDEM 2008
This is an earlier presentation held at FOSDEM 2008 in Brussels, available as HTML with CSS for online viewing: http://www.poeml.de/~poeml/talks/redirector/. It is also available as video recording in ogg format (350MB), google video and on blip.tv.