Define Drainstop

For Network Load Balancing, a command that disables all new traffic handling on the specified hosts. The hosts then enter draining mode to complete existing connections.
While draining, hosts remain in the cluster and stop their cluster operations when there are no more active connections. To terminate draining mode, explicitly stop cluster mode with the stop command, or restart new traffic handling with the start command. To drain connections from a specific port, use the drain command.