Introduction
A content delivery network or Content Delivery Network (CDN) is a system of computers containing copies of data, placed at various points in a network so as to maximize bandwidth for access to the data from clients throughout the network. A client accesses a copy of the data near to the client, as opposed to all clients accessing the same central server, thereby causing a bottleneck near that server.
Goals
- Reduce bandwidth at primary download server.
- Improve quality of service for users.
- Move content closer to users, thus reducing latency.
Mirrors
The current list of available mirrors is available at http://mirrors.sugarlabs.org/
Setting up a Mirror
Setting up a mirror is very easy. All you need is a web server which is available via http, and (if possible) rsync.
Please contact sysadmin AT sugarlabs DOT org if you are interested in hosting a mirror.
System Summary
The Sugar Labs Content Delivery Network uses MirrorBrain as a redirector. The redirector, which lives in a Sugar Labs data center, keeps track of which files are available on which mirror. When a user requests a file, the redirector points the user to the correct mirror and automatically starts the file download.
Mirrors
Mirrors are completely passive. To set up a mirror, a mirror system administrator needs to:
- Set up rsync job to synchronize a copy of the files on http://downloads.sugarlabs.org onto their local system.
- Publish the files via HTTP and -- if possible -- rsync. Rsync allows for efficient mirror monitoring (scanning). FTP is less efficient, but still preferred over an HTTP-only mirror.
- Alert the Sugar Labs system administrators that they would like their mirror into rotation, including the following information in the request:
- Name and URL of the mirror operator (e.g. organisation)
- Name and email address of the administrative contact
- ISO 3166-1 alpha-2 country code of the server location
- HTTP base URL of the files on the mirror
- rsync base URL of the files on the mirror
Adding a new mirror to the Mirror Brain redirector
- Choose a name for the mirror, usually the host name.
- Register the mirror with MirrorBrain:
sudo -u mirrorbrain mb new <mirror name> --operator-name <operator name> \ --operator-url <operator URL> -a <admin name> -e <admin email> \ -c <country code> -H <base HTTP URL> -R <base rsync URL> -F <base FTP URL>
- Scan and enable the mirror:
sudo -u mirrorbrain mb scan -e <mirror name>