Understanding the RTCS system registry
The RTCS system registry is backed by a VSAM LDS, whose DSNAME is specified by the SREGVLDS option in the RTCS initialization member of Logical PARMLIB. The z/OS Data-In-Virtual (DIV) service writes all changes that are made to the contents of the registry to the LDS.
Each z/OS image requires some form of access to the data in the registry VSAM LDS. A single VSAM LDS can be shared among all members of the sysplex or a dedicated VSAM LDS can be used for each individual z/OS system image. BMC recommends that you share a single VSAM LDS among all members of a sysplex. The MainView CAS places certain configuration information in the registry in order to make it available to all CASs in the sysplex. If you do not share a single VSAM LDS for the registry, you will not be able to take advantage of this CAS function.
A dedicated VSAM LDS can be configured for each RTCS subsystem or a single VSAM LDS can be shared by all members of the sysplex. If sharing a VSAM LDS, only one member actually allocates the registry VLDS with DISP=OLD, but the data in the registry is made available to other (remote) members of the sysplex using the XCF communications facility of z/OS.
For more information, see the following topics:
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