Service/mirrors

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Revision as of 05:10, 24 July 2011 by Sascha silbe (talk | contribs) (Instructions for adding a mirror, minor changes)
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Introduction

A content delivery network or content distribution 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.

Mirrors

The current list of available mirrors is available at http://mirrors.sugarlabs.org/

Goals

  • Reduce bandwidth at primary download server.
  • Improve quality of service for users.
  • Move content closer to users.

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 systems@sugarlabs.org if you are interested.

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 synchronise a copy of the files on 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

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>