Hey, I have an extension to PHP that enables the session management extension to spread across multiple web servers easily. It used to be called "msession" and an old broken version is still included in PHP. I have just finished up a new version of it, fixed a lot of bugs, and added a better persistent session storage system.
If you are struggling with a number of web servers behind a load balancer and need a solution, I'd like you to try MCache and tell me what you think. I need testers.
It has been lightly tested on PHP 4.4.5 and should work on later versions. It is in beta and I am looking for help with it. MCache is GPL and the Phoenix library it requires is LGPL.
You can find it at http://www.mohawksoft.org. Look at the "MCache Handbook" for more information. There are two tarballs under "Download."
What I need: Does it compile on your machines? (If not, what are your problems?) How does it perform? It is probably not 64bit compatible, but I am willing to work with someone with a 64 bit machine to make it so. Anything else you want to help out with.
I think this is a neat system for reasonably sized web farms and could potentially make clustered PHP a snap.