Sharing sessions between servers

[Anon]

Dear Cookie-people and Sessions users:

I'm using sessions with PHP4 currently, and I know that cookies are limited to the host, although internal page elements can access other servers and pass on variables, redirection, etc.

If I have a server, such as www.mydomain.com and another that it download.mydomain.com, and they both access the same session directory and databases... What is the best way to be able to continue using sessions between the two?

Can session_id= simply be included via GET, or does a function need to check if it should share session information?

Any ideas or thoughts would be great.

[Anon]

Won't work. Here's why. Sessions store the registered variables in temp files on the server and use the SESSID cookie to locate those files. If you have multiple servers -- even multiple servers with the same name on a round-robin server farm -- the model breaks. You have to share the filesystem as well.

Cookies can be shared across multiple machines, though, and across multiple secondary domains as well.

[Anon]

Some great ideas for solving this issue.

http://www.phpbuilder.com/forum/read.php3?num=1&id=121340&thread=121331