IMS Connect support for z/OS Sysplex Distributor

IMS Connect includes a variety of features that facilitate its execution in a z/OS® Sysplex Distributor environment.

In a z/OS Sysplex Distributor environment, incoming messages are typically distributed among multiple instances of IMS Connect to balance the workload and increase availability. In such an environment, client applications have no control over which instance of IMS Connect receives their input messages and which IMS Connect receives subsequent requests for asynchronous output. IMS Connect, with OTMA, provides several features to support operating in such an environment, such as rerouting asynchronous output to an alternate tpipe, sharing asynchronous output by using an OTMA super member tpipe, retrieving output from an alternate tpipe queue associated with another client, and purging undeliverable output.

IMS Connect automatically sends a server health status report to z/OS Workload Manager (WLM) when the server is started. The health status is a number in the range 0 - 100 that indicates the health of IMS Connect and is initially set to 100. The health value is defined based on the available socket percentage, which is the number of available sockets as a percentage of the maximum allowable number of sockets that is set by the MAXSOC parameter in the TCPIP configuration statement. The available socket percentage and the corresponding health status number are mapped in the following way:
  • If the maximum allowable socket number is equal to or greater than 1000 (MAXSOC >= 1000):
    • If the available socket percentage is 11% - 100%, the health status number is 100.
    • If the available socket percentage is 0% - 10%, the health status number is equivalent to the number of the available socket percentage, which is 0 - 10.
  • If the maximum allowable socket number is less than 1000 (MAXSOC < 1000):
    • If the available socket percentage is 21% - 100%, the health status number is 100.
    • If the available socket percentage is 0% - 20%, the health status number is equivalent to the number of the available socket percentage, which is 0 - 20.
An updated health status report is sent when the server health changes.

z/OS Sysplex Distributor uses this information to route incoming connections when the distribution method SERVERWLM is specified on the VIPADISTRIBUTE statement of the z/OS TCP/IP profile. You can also set the SHAREPORTWLM parameter for the PORT definition to configure Sysplex Distributor to use the WLM health status to balance incoming connections between two or more instances of IMS Connect that are running on the same host with a shared port.