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<UL><LI>IMS is providing Sysplex enhancements for both the IMS Database and Transaction Manager.
<LI>IMS will take advantage of z/OS's Coupling Facility (CF) duplexing function for IMS Shared Message Queue structures and IMS Fast Path Expedited Message Handler (EMH) structures. When CF duplexing is enabled, z/OS creates a duplex copy of the structure for failure recovery. If the IMS Shared Queues structure or the EMH structure fails or a connection to the structure is lost, z/OS switches to the unaffected structure instance without the overhead of a structure rebuild. CF duplexing also enables system-managed rebuild. MVS does the structure rebuild for a planned reconfiguration to do the structure copy if no IMS Common Queue Server (CQS) is up. The advantage to system rebuild is that CQS does not have to be up. CQS managed rebuild is still needed to address CF failure, structure failure, or loss of connectivity.
<LI>CF Structure Duplexing support for IMS Data Sharing is being provided through the IRLM 2.1 service process.
<LI>IMS is also providing the following IMS Fast Path Virtual Storage Option (VSO) Coupling Facility (CF) enhancements through the IMS Version 7 service process:
<LI> - System-managed rebuild provides for rebuilding a VSO structure to enable migration of a VSO structure from one CF to another for planned reconfiguration without taking the VSO structure offline. All structures can thus be migrated using a single command.
<LI> - Automatic Altering of VSO structure size and entry-to-element ratio provides for dynamically expanding or contracting a VSO structure based on its actual CF storage usage with exclusive control as needed. Over-configured CF storage can be reclaimed when OS/390 and/or zOS need CF storage.
<LI> - System Managed Duplexing of VSO structures allowing dual VSO structure support without explicitly defining both primary and secondary structures in IMS Database Recovery Control (DBRC) Facility and in a CFRM policy. It provides for the automatic switch of modes when a loss of connectivity, a structure failure, or a CF failure occurs in one of the VSO structure instances. </UL>
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