IMS catalog multi-system configuration examples

The following figures show some of the multi-system configurations that are possible with the IMS catalog.

Multiple IMS systems with one IMS catalog

In the following example, all of the IMS systems in a multi-system environment share a single catalog database. The attributes of the IMS catalog are defined in a single <CATALOG> section of a single DFSDFxxx member that all of the IMS systems reference. The systems also share ACB library data sets.

Figure 1. Two IMS systems with a shared catalog database
begin figure description. Two IMS systems use a shared catalog database in a multi-system environment by sharing a single <CATALOG> section of a shared PROCLIB member. end figure description

Multiple IMS systems with one IMS catalog and IMS-managed ACBs

In the following example, all of the IMS systems in a multi-system environment share a single catalog database. The IMS management of ACBs is enabled for both IMS systems by a specification of ACBMGMT=CATALOG in the <CATALOG> section of a single DFSDFxxx member that all of the IMS systems reference. ACB library data sets are not used.

Figure 2. Two IMS systems with a shared catalog database and IMS-managed ACBs
begin figure description. Two IMS systems use a shared catalog database in a multi-system environment by sharing a single <CATALOG> section of a shared PROCLIB member. end figure description

Multiple IMS systems with independent IMS catalogs

In the following example, each IMS system in a sysplex maintains its own IMS catalog. In order to prevent name conflicts between separate catalog databases that use the same default name on multiple systems, each system has a configurable alias name in the DFSDFxxx PROCLIB member. The alias name masks the default catalog database name. The following figure shows an example of this scenario where two IMS systems in a multi-system environment maintain their own catalog databases. In this scenario, the IMS systems in the multi-system environment have independent catalogs that are specified with separate <CATALOGxxxx> sections of a shared DFSDFxxx IMS.PROCLIB member.

Figure 3. Two IMS systems with independent catalog databases in a multi-system environment
begin figure description. Two IMS systems use independent catalog databases by specifying separate <CATALOGxxxx> sections in a shared PROCLIB member. end figure description

The following example is the same as the preceding example, except that each IMS system maintains its own DFSDFxxx PROCLIB member. As a result, each system uses the <CATALOG> section heading instead of the <CATALOGxxxx> section heading.

Figure 4. Two IMS systems with independent catalog databases and individual IMS.PROCLIB members in a multi-system environment
begin figure description. Two IMS systems use independent catalog databases. Each system uses a CATALOG section in a different, unshared PROCLIB member. end figure description.

Multiple IMS systems with independent IMS catalogs and IMS-managed ACBs

In the following example, each IMS system in a sysplex maintains its own IMS catalog. The two IMS systems share a DFSDFxxx member but each uses a separate <CATALOGxxxx> section to define a different alias name for each IMS catalog. The IMS management of ACBs is enabled for each IMS system by a specification of ACBMGMT=CATALOG in each <CATALOGxxxx> section, so ACB library data sets are not used.

Figure 5. Two IMS systems with independent catalog databases in a multi-system environment
begin figure description. Two IMS systems use independent catalog databases by specifying separate <CATALOGxxxx> sections in a shared PROCLIB member. end figure description

A mixed-case example with IMS-managed ACBs

A single multi-system environment can contain both a shared IMS catalog that is used by some IMS systems, as well as one or more independent IMS catalogs that are each used by only one IMS system. However, any single environment can contain only one shared catalog database and each IMS system can use only one catalog database at a time.

In the following example, IMS1 and IMS2 share IMS catalog CAT1 while IMS3 has its own IMS catalog, CAT3.

Figure 6. Two IMS systems with independent catalog databases in a multi-system environment
begin figure description. A multi-system environment includes three IMS systems. Two IMS systems share IMS catalog CAT1, as specified by ALIAS=CAT1 in separate DFSDFxxx members. A third IMS system, uses an independent IMS catalog, CAT3, as specified by ALIAS=CAT3 in its own DFSFxxx member. end figure description