Concurrent websocket connections a tomcat instance

[robinvk6]

This is more of a question.
What is the max number of concurrent websocket connections a tomcat instance can support? We are looking to serve 20000 connections at any given time. What would be the recommended number of tomcat instances to support the load?

[sreeshas]

A WebSocket is a TCP socket. The total number of websocket connections are determined by number of open file descriptors permitted by OS on which websocket server( tomcat instance in this case) is running.

[robinvk6]

On a unix machine we have a hard limit of 75000 file descriptors but is there a Hard limit on tomcat's ability to spawn new sockets?