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Overview of VSAM RLS z/OS DFSMStvs Planning and Operating Guide SC23-6877-00 |
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VSAM RLS processing involves support from multiple products:
With VSAM RLS, multiple CICS systems can directly access a shared VSAM data set, eliminating the need to ship functions between the application-owning regions and file-owning regions. CICS provides the logging, commit, and backout functions for VSAM recoverable data sets. VSAM RLS provides record-level serialization and cross-system caching. CICSVR provides a forward recovery utility. The level of sharing that is allowed between applications is determined
by whether or not a data set is recoverable. For example:
VSAM RLS uses a coupling facility to perform data set-level locking, record locking, and data caching. VSAM RLS uses the conditional write and cross-invalidate functions of the coupling facility cache structure, thereby avoiding the need for control interval (CI) level locking. VSAM RLS uses the coupling facility caches as store-through caches. When a control interval of data is written, it is written to both the coupling facility cache and to direct access storage device (DASD). This ensures that problems occurring with a coupling facility cache do not result in the loss of VSAM data. |
Copyright IBM Corporation 1990, 2014
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