Shared temporary storage queues are stored in named pools in an MVS™ coupling facility. Each pool corresponds to a list structure in a coupling facility. Access to queues stored in the coupling facility is quicker than function shipping to a QOR.
A temporary storage server provides better availability than a QOR because you can have more than one temporary storage server for each pool (typically one server in each MVS image in the sysplex). If one temporary storage server or MVS image fails, transactions can be dynamically routed to another AOR on a different MVS image.
Local TS queues offer less performance overhead than a QOR. However, local queues can cause intertransaction affinities, forcing affected transactions to run in the same AOR so that they can access the local queue. This affects performance by inhibiting dynamic routing and preventing workload balancing across the AORs in the sysplex. Intertransaction affinities can be managed by a workload management function provided by CICSPlex® SM, but you must provide intertransaction affinities definitions for the affected transactions. The CICS/ESA 3.3 XRF Guide gives guidance about determining where the affinities are in your application programs. Temporary storage data sharing removes the need for the time and effort that this systems management demands by avoiding intertransaction affinity. In general, the overall workload balancing benefits provided by being able to use dynamic transaction routing to any AOR should outweigh any overhead incurred by the temporary storage servers.