Work load management and clustering

Clustering application servers that host Web containers automatically enables plug-in workload management for the application servers and the servlets they host. Routing of servlet requests occurs between the Web server plug-in and the clustered application servers using HTTP or HTTPS

This routing is based on weights associated with the cluster members. If all cluster members have identical weights, the plug-in sends equal requests to all members of the cluster, assuming no strong affinity configurations. If the weights are scaled in the range from 0 to 20, the plug-in routes requests to those cluster members with the higher weight value more often. No requests are sent to cluster members with a weight of 0 unless no other servers are available.

Weights can be changed dynamically during runtime by the administrator. A guideline formula for determining routing preference is:

% routed to Server1 = weight1 / (weight1+weight2+...+weightn)

Where there are n cluster members in the cluster.
The Web server plug-in temporarily routes around unavailable cluster members