Optimizing local connections

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 useful if your environment includes multi-tier server applications within a single sysplex. In this environment, if communication between the tiers is based on the TCP protocol, sysplex distributor can provide higher server availability. For example, without sysplex distributor or some other form of IP load balancing, when an application in tier 1 tries to connect to a tier 2 application on the local system, if the tier 2 server application is not available, these connections fail and the workload is disrupted. Sysplex distributor dynamically reroutes these connections to another tier 2 application that is running elsewhere in the sysplex, which provides a high availability solution. You can use the OPTLOCAL keyword to further optimize load balancing for this type of configuration; for more information about the OPTLOCAL keyword, see Sysplex distribution optimizations for multi-tier z/OS workloads.

Tip: In networks that have CISCO routers, it might be possible to remove the requirement that all inbound traffic needs to traverse the distributing stack. For more details, see Optimized connection load balancing using sysplex distributor in a network with CISCO routers (IPv4 only).

Sysplex distributor also enhances the dynamic VIPA and automatic VIPA takeover functions. The enhancements allow a DVIPA to move nondisruptively to another stack. That is, in the past, a DVIPA was allowed to be active only on one single stack in the sysplex. This led to potential disruptions in service when connections existed on one stack, yet the intent was to move the DVIPA to another stack. With sysplex distributor, the movement of DVIPAs can now occur without disrupting existing connections on the original DVIPA owning stack.

See Configuring distributed DVIPAs — sysplex distributor for more information.