Sysplex distribution optimizations for multi-tier z/OS workloads

You can configure sysplex distributor to optimize connections when both connection endpoints potentially are on the same TCP/IP stack within the sysplex. This feature can be very useful in environments in which multi-tier server applications are located within the same z/OS® system images in a single sysplex. In this environment, if communication between the tiers is based on the TCP protocol, you can use sysplex distributor to provide higher availability.

For example, without sysplex distributor or some other form of IP load balancing, if an application in tier 1 tries to connect to a tier 2 application on the local system, but the tier 2 server application is not available, then these connections fail and the workload is disrupted. With sysplex distributor, these connections are dynamically rerouted to another tier 2 application that is running elsewhere in the sysplex, which provides a high availability solution.

Examples of tier 1 server applications on z/OS that can be used with tier 2 server applications on the same z/OS logical partition (LPAR) are the IBM® HTTP Server, the CICS® Transaction Gateway, and the WebSphere® Application Server. Examples of applications that can be used as tier 2 servers in the same z/OS system and sysplex as tier 1 servers are the CICS Transaction Server, IMS™ Connect, and DB2®.