I'm looking for TCP load balancing software that health checks the upstream servers.
The problem with the load balancers I've seen is that they have no limit on what they will remove from rotation. A spike in load will cause a one health check to fail, so the host is removed and a cascading effect and eventually nothing is left in rotation, and the situation is irrecoverable without manual intervention.
Some issues can be fixed by removing unhealthy hosts, but few problems can be solved by removing all of them.
I'm looking for a load balancer with health checks but also a minimum on the number of hosts in rotation, to prevent collapsing into this irrecoverable situation.
The load balancer can be for any OS, any price, and any license.