The CICS® Performance Series is a collection of IBM® Redpaper™ publications that are focused on the performance of customer information control systems (CICS) and written by members of the IBM Hursley CICS development community. The topics are chosen based on feedback from CICS customers, with the goal of expanding readers’ understanding of the rich features that are offered by the CICS Transaction Server (CICS TS) product portfolio.

The objectives of this publication are threefold:

- Show comparisons and performance characteristics of a simple workload accessing VSAM data .

- Outline and explain the CICS and RLS activities that occur when a CICS program issues various API calls to RLS, specifically READ, READ UPDATE, REWRITE, ADD, BROWSE, and DELETE.

- Document how monitoring data that is generated by CICS, RMF, and SMS can be extracted and correlated, and explain some of the key fields that you can examine to determine if configuration or usage patterns can be optimized.

To achieve these objectives, this paper provides an overview of CICS and RLS concepts, terms, and components. It then follows up with some specific CICS migration scenarios that explain why customers should consider migrating to SMS-managed RLS datasets.