When a session is launched, a method is called that selects the best SPS node based on managed network settings and SPS fitness score The fitness score is calculated from SPS metrics such as disk usage and CPU load. This is not a optimal load balancing implementation, SPP is trying to ensure a session is not sent to a failed or overloaded appliance.
NOTE: In versions below 6.7 and 6.0.7, SPP can incorrectly select the SPS node with the highest load / highest diskusage. This is resolved from 6.7 and 6.0.7.