Content Distribution

mirror

A Perl script commonly used to synchronize FTP archives over, you guessed it, FTP. By it's nature though, FTP does not scale well for this purpose -- mirror degrades as the amount of content grows.

rdist

A really simple tool, rdist will read instructions from a distfile and invoke remote instances to synchronize files and their attributes (including ownerships, permissions, and modified times).

rsync

Similar but it does a few things smarter:

• it can send just the delta required to make two file alike, instead of sending the whole file
• one need not define a separate file for synchronization instructions, everything rsync needs to do is easily expressed on a command line

Distributing content to more than one server, however, requires starting up more than one instance of rsync. Instead of having a content source "push" the content to the servers, one could have the servers "poll and pull" from the content source; rsync supports running a server process that permits connections such as this.