Scalable, Fault-Tolerant TCP Connections?

pauljlucas asks: "My company is developing custom server software for an instant messaging type server (under Solaris). Every client maintains a TCP connection to the server when it is 'logged in'; the server maintains state of who's logged in where. For large-scale deployment, there are two problems: scalability and fault-tolerance. A single server can handle at most around 64000 open sockets. To go beyond this, you need many servers. Another way would be to 'fake' a TCP stack in user-space (by reading/writing raw TCP packets) thus not having one real socket per connection. For fault-tolerance, ideally one would like N servers to maintain the exact state, at least for the server process, so that if one goes off line, the other(s) can pick up seamlessly. I'm thinking that both of these issues must have already been solved without having to write lots of custom software. Is anybody aware of off-the-shelf software and/or hardware solutions (either commercial or freeware)?"

Comments

LocalDirector

[Huusker]

You can get a TCP load balancer like Cisco LocalDirector or one its competing clones. They are expensive tho ($20,000)