Determining which applications should use DFSMStvs

You can determine which of your installation's applications should use DFSMStvs support by sorting them into these categories:


DFSMStvs intolerant applications: These applications use facilities that VSAM RLS does not support, access VSAM internal data structures, or are incompatible with VSAM RLS and DFSMStvs sharing.
DFSMStvs tolerant applications: These applications operate correctly in a multiple-updater environment when you specify either record-level sharing (RLS) in the JCL (job control language) or MACRF=RLS in the ACB (access control block). Without further modifications to an application, however, specifying RLS mode would make the entire application a single unit of recovery. RLS mode would also cause locks and log data to be kept for the length of the job. This could impact system resources and performance.
For these reasons, do not convert this type of application to use DFSMStvs access without additional application modification.
DFSMStvs exploiting applications: These applications recognize data sets that can be accessed using DFSMStvs, and they use DFSMStvs to access those data sets. Such an application also understands the scope of changes and sync points and makes use of resource recovery services (RRS) for commit and backout. These applications can read and write recoverable data sets that are concurrently in use by CICS®.