There are several good reasons to mirror a Linux repository, be it the Zend repositories or any other repository. The most simple reason is sheer performance: if you need to install Zend Server on a number of machines, you can save a lot of valuable time by creating a local mirror of the repositories, and using that mirror as your installation source for all servers.

He also points out that it can save on bandwidth used - pulling from local will always be more efficient. It also gives you more control about exactly what software is installed on your servers. He breaks the mirroring process up into four steps (with a few added helpful hints at the end):

• Copy the Zend Server repository to a local machine
• Local Repository Test
• Enable network access to your local repository
• Configure clients to use your local repository

As you might have noticed if you follow me on Twitter (which you should do as I make a lot of small announcements there), or if you monitor the Subversion activity closely, the Symfony 2 code is now hosted on Git. [...] So, from now on, all the development activity for Symfony 2 will take place on the new Git repository.

He briefly covers what git is and a resource (book) he used to help understand this recently popular version control system. If you don't want to learn a new version control system but still want to contribute back with the subversion knowledge you're already armed with, you can still use their svn mirror to get the latest releases.

The Phing and Propel Subversion repositories have suffered from long downtime periods quite often recently (last one was today). It is quite annoying as when it happens, you cannot easily update your symfony repositories, let alone the checkout of a symfony branch. To make things worse, the Doctrine repository also had some problems recently. A lot of symfony users are quite upset by the situation, myself being the first one.

The solution - create some mirrors to provide more than one source to fetch the latest checkouts from. Here's the list of the new resources: Phing mirror, Propel mirror, Doctrine mirror.

In addition to [a local copy of your source] being faster to develop, it lets you work without needing to be connected to the Internet. But what about the tools you use while developing? If you're a PHP developer then the manual at php.net is an invaluable tool. It only make sense to have it available for when you're not online.

His example follows the official mirroring part of the PHP.net website and uses a slightly modified rsync command to fetch the manual information from the php.net site and drops it in a location locally. He throws in an Apache configuration too for a simple VirtualHost to get it up and running.

I'm excited to announce the first two mirrors of pear.php.net are now actively mirroring the installer REST files and actual .tgz files of package releases. They are http://us.pear.php.net (provided by Joshua Eichorn and bluga.net) and http://de.pear.php.net (provided by Christian Weiske). The option exists at a future date of mirroring the entire website, but this will not be possible without further changes to the infrastructure.

Using these servers is only slightly different than the main site, setting the preferred_mirror setting in your configuration to use one of the above.

At the moment were only mirroring installer data not the entire website but its a start. Things are still in the testing phase, but the mirror is usable, just run: pear config-set preferred_mirror us.pear.php.net

The update runs every four hours, so thing might be a little out of sync sometimes, but if you're just looking to keep things up-to-date, that's more than enough.

caching services such as coral content distribution network provide an alternative for when your site goes down, but why wait until it gets to that stage? why not just send all your hits from high-end websites to the coral cache version? well, there isn't a good reason not to, so i'll show you how to do it automatically.

He provides the simple script that looks for certain sites in the "HTTP_REFERER" value of incoming calls and pushes them off to the cached location with a header() redirect. The whole thing is only 12 lines, not counting the $sites array.