Thread

We have a great need to scale out an expression engine site to multiple, replicated servers, but have noticed that several key functions of expression engine rely on $SESS and as we are replicating out to multiple servers, we can’t really share session between them.

I have made a few core modifications to write back to a master database for things like comments, orders, etc…, but cannot figure out a way to successfully use captcha without relying on session.

My biggest problem is navigating the codebase to find where the captcha value is checked. I’ve found the create_captcha function (and our hooked version in an extension) and have modified my tokens to write to a master database, I just can’t find where that captcha value is checked on the postback.

Any help would be greatly appreciated.

Best regards,

Hal

Hi, Hal,

ExpressionEngine can absolutely be load balanced, but doing so through replication is not recommended for exactly the reasons that you describe.  Have you searched the forums for load balancing and load balance and read the posts by Nevin Lyne?  That is an incredible resource; what it comes down to is that the load balancing should be invisible to the software.

I’ll also move this down to How to for you; I would highly recommend steering away from the hacks, though, as you’re going to make it quite difficult to upgrade later.