How to keep session data in multiple Apache servers

[moiz_siddiqui]

Hi everyone,

We plan to install multiple Apache servers instead of single Apache server since it is overloaded. My concern is: in one user session, the user may send 2 or more requests. How do multiple Apache servers to communicate each other for the same session?

Our team has figured that we should use a common database between the two servers. Have all of your user session data stored there. Then either server can access the data at any time.

Although it is a good solution but is there any alternat way to implement this problem????

[Roger_Ramjet]

Probably, but I doubt it would be any better. I mean there are people like Rackspace that offer virtual servers based on multiple boxes for high fault tollerance, they must have solved that issue. But I'd bet the software don't come cheap.

Anyway, session data is stored in text files on disk, so it involves disk I/O just like a database solution. Seems one would be about as efficient as the other if you get the db structure and query right, and it's really just serialise the session array into a text field so how hard can that be. That's all the session does, serialise the array into a text file.

The one issue that will slow the db solution down is network latency from the apache boxes to the db server. How fast is the backbone gonna be? And the db server itself of course?

Thinks?? Why not distibute the files around several servers but use 1 for user connection? So all session data would be on the box where index.php is, but all the graphics files and other parts would be served from other boxes through eg mod-rewrites.

[Weedpacket]

Whatever solution you come up with, you can use PHP's session-handling functions as-is by writing handlers for your solution and registering them with [man]session_set_save_handler[/man].