There are situations where a load balancer using round-robin distribution doesn't allocate users or sessions evenly between clustered servers. This can create an imbalance so that one of the servers may have many more sessions or users than other server(s) in the cluster.
Even though the FVHealth.aspx will report available sessions (or users if user-based licensing) for each server when requested by a load balancer, the available logic on load balancers generally is not sophisticated enough to compare the numbers between servers as may be possible with CPU-based allocation.
By setting the Server Report Over Percentage to a value other than 0, the server will compare active sessions or users to other server(s) in the cluster. If the server calculates that the number of available sessions is under other servers by the stated percentage, instead of reporting "ACTIVE" it will report "OVER". If Server Unavailable Response Code is set to something other than 200, it will report that (such as the recommended 503 for simplistic load balancer logic).
This should then prevent new sessions/users to be allocated to this server until the percentage is more in-line with other server(s) in the cluster.
Available Values:
0: Report Over Not Active |
No calculations are performed and "ACTIVE" will be reported up until no sessions are available. |
10% Report Over if 10% or higher than other servers |
Calculations will be made and "OVER" will be reported if this server has 10% fewer available sessions than other servers |
20% Report Over if 20% or higher than other servers |
Calculations will be made and "OVER" will be reported if this server has 20% fewer available sessions than other servers |
30% Report Over if 30% or higher than other servers |
Calculations will be made and "OVER" will be reported if this server has 30% fewer available sessions than other servers |
