Scalable architecture

[eluser]eoinmcg[/eluser]
virtual hosts allow you to server multiple sites from one web server.

you can read more about symbolic links here: http://en.wikipedia.org/wiki/Symbolic_link

so, let's assume your webserver looks something like this:
/home/txomin/public_html/site1/
/home/txomin/public_html/site2/
/home/txomin/public_html/site3/

if these three sites are all running more or less the same code updating one by one is going to be a bit of a timewaster. so, if we create a 'master' site
/home/txomin/public_html/master

then you in each of the sites you can create a symbolic link back to your codeigniter app, for example:
ln -s /home/txomin/public_html/master/system /home/txomin/public_html/site1/system

no how that would work on windows though

alternatively, you could use some form of version control (SVN, GIT etc) and update each site by checking out the master copy