If you have a hardware load balancing device configured, the threshold value represents the percentage of incoming traffic that a server can receive before the load balancing device redirects the traffic to another Web server.
If you do not have a hardware load balancing device configured with ColdFusion and you have a system probe and alarms set up in ColdFusion, the threshold value defines when the ColdFusion server is busy. The ColdFusion Server alerts you when the threshold exceeds the threshold value specified on the Server Configuration page.