Tuxedo - LDBAL

Load balancing is a technique used by the BEA Tuxedo system for distributing service requests evenly among servers that offer the same service. This avoids overburdening some servers while leaving others idle or infrequently used. Before sending a request to a service routine, the system identifies all servers capable of handling the request and selects the one most appropriate for maintaining a balanced load across all the servers in the configuration.

Enabling Load Balancing

If you set the RESOURCES section parameter LDBAL to Y, server load balancing occurs. A LOAD factor is assigned to each service performed, which keeps track of the total load of services that each server has performed. Each service request is routed to the server with the smallest total load. The routing of that request causes the server's total to be increased by the LOAD factor of the service requested.

Load information is stored only on the site originating the service request. It would be inefficient for the TUXEDO system to attempt to constantly propagate load information to all sites in a distributed application. When performing load balancing in such an environment, each site knows only about the load it originated and performs load balancing accordingly. This means that each site has different load statistics for a given server (or queue). The server perceived as being the least busy differs across sites.

When load balancing is not activated, and multiple servers offer the same service, the first available queue receives the request.

Note: Such as algorithm should be used only when necessary, that is, only when a service is offered by servers that use more than one queues. Services offered by only one server, or by multiple servers in an MSSQ (Multiple Server, Single Queue) do not need load balancing. The LDBAL parameter for these services should be set to N. In other cases, you may want to set LDBAL to Y.