Is there some kind of HttpSession server out there?

[Woraphol Janekittanpaiboon]

Dear all,

First of all sorry for my poor English, I would like to create web apps using Servlet technology
running on a large cluster of Tomcat instances.
Performance is what I care the most and as you know session replication across a cluster degrades
system performance significantly since they need to communicate with each other to learn what has
happened to the sessions each stores.
I have an idea to create a kind of centralized session server (or a cluster of it for failover) that stores all the
sessions used for Tomcat instances. What each web server needs when it wants to get access to
a session object is to create a connection to the server and retrieve a session in return. Doing this will also get rid
of the need of sticky session since an Http request can be passed through any web server knowing that it will be using the same
session object.
I think Memcached would be a good candidate but since it lacks replication and fail over thus the sessions
can disappear if a server go down which of course is the last thing you want when handling with precious user sessions.
Is there a kind of this type of server out there so I will not have to reinvent the wheel?

Regards,
Woraphol

[Tim Holloway]

If you're using Tomcat, there's supposed to be a facility where the different Tomcats in the cluster can share a database for Sessions. I've never tried it, however.

Why don't you ask about it in our Tomcat Forum? We do have people who do major clustering over there. Although you might want to check out the Tomcat docs first so you'll be better equipped to ask the question in a way everyone can understand.

[Madhan Sundararajan Devaki]

I believe, using a load balancer, will take care of sessions during failover.