DYNAMIC_RESOURCES section of the DFSDFxxx member

Parameters

These parameters are applicable only in a DRD environment; they are ignored in a non-DRD environment.

AUTOEXPORT=AUTO | NO | RDDS | REPO

Specifies whether all resource and descriptor definitions are exported at checkpoint time (simple or normal shutdown).

The automatic export takes place only if definitional changes were made to any resource since the time of the last checkpoint, except for restart checkpoint. After IMS completes restart processing, a restart checkpoint is taken. Export occurs after the restart checkpoint if automatic export is enabled.

AUTO

IMS determines whether to enable automatic export.

If AUTOEXPORT=AUTO is specified or defaulted to, automatic export is enabled to the system resource definition data set (RDDS) if two or more system RDDSs are defined and accessible.

If AUTOEXPORT=AUTO is explicitly specified in the DFSDFxxx PROCLIB member and IMS is enabled to use the IMSRSC repository, automatic export is also enabled to the IMSRSC repository.

If AUTOEXPORT=AUTO is defaulted to, automatic export to the repository is not enabled even if IMS is enabled with the repository.

If AUTOEXPORT=AUTO is specified in the DFSDFxxx PROCLIB member and both the repository and two or more system RDDSs are defined and accessible, automatic export is enabled to both the repository and the RDDS.

NO

Disables automatic export. No resource or descriptor definitions are exported at checkpoint time.

RDDS

Automatic export is enabled if two or more system resource definition data sets are defined and accessible. All resource and descriptor definitions are exported to the oldest system resource definition data set at checkpoint time.

REPO

IMS automatically exports resource definitions to the IMSRSC repository if IMS is enabled to use the repository. If IMS is not enabled with the IMSRSC repository, set AUTOEXPORT=NO to disable automatic export.

If AUTOEXPORT=RDDS is specified, IMS automatically exports to an RDDS if a valid system RDDS exists, even if the REPOSITORY section of the DFSDFxxx member is defined and IMS is enabled to use the repository. With this behavior, you can have a valid RDDS during a migration to the repository. After a successful migration to the repository, you can disable automatic export to an RDDS by using the UPDATE IMS SET(LCLPARM(AUTOEXPORT(N))) command.

AUTOEXPORT_IMSID=THIS_IMS | ALL

Specifies how automatic export processing should write the resource definitions to the IMSRSC repository and the IMS IDs for which the resource definitions are defined.

Note: AUTOEXPORT_IMSID applies only if automatic export is enabled to the IMSRSC repository. If the automatic export to the repository is not enabled, this parameter is ignored.

THIS_IMS

Writes the resource definitions from this IMS to the IMSRSC repository for the IMS system that is processing the automatic export. If the resource definition exists in the repository for the IMS system that is processing the automatic export, the definition is updated. If the resource definition does not exist in the repository for the IMS system that is processing the automatic export, it is created and the resource name is added to the IMS resource list of the IMS that is processing the automatic export. If there are multiple IMS systems in the IMSplex, each IMS creates or updates the resource definition for itself during its automatic export processing.

If AUTOEXPORT_IMSID=THIS_IMS is specified, only the resource definition changes to the specified IMS ID are exported. An X'22' log record is written by all IMS systems that initiated the automatic export.

After an automatic export to the repository with AUTOEXPORT_IMSID=THIS_IMS, the QUERY XXX SHOW(DEFN) command output will show a response line for each IMS until the automatic export from the last IMS that has the resource defined takes place. When RM processes the automatic export request from the last IMS that has the resource definition defined, RM internally analyzes the repository definition and merge any IMS definitions to optimize storage use in the repository.

After a successful automatic export to the repository from the last IMS that has the resources defined, there will not be any IMS specific response lines on the QUERY XXX SHOW(DEFN) commands if all the IMS systems have the same resource definitions.

If the resource definitions are not cloned in the IMSplex, use AUTOEXPORT_IMSID=THIS_IMS. This specification is equivalent to not specifying SET(IMSID()) or specifying SET(IMSID(imsid)) of the IMS system on the EXPORT DEFN TARGET(REPO) command. When the last IMS that has the resource defined does its automatic export, RM will compare the attribute definitions for all IMS systems and merge the resource definition into a generic definition to save space in the repository.

ALL

Writes the resource definitions from this IMS to the IMSRSC repository for all IMS systems that are defined to use the repository. If the resource definition exists in the repository, it is updated. If the resource definition does not exist in the repository, it is created and the resource name is added to the IMS resource lists for all the IMS systems that are defined to use the repository.

If AUTOEXPORT_IMSID=ALL is specified, automatic export is requested to the Resource Manager (RM) so that RM exports the resource definition changes to all the IMS IDs that have the resource defined. Only the IMS global resource definition in the repository is updated. An X'22' log record is written only at the IMS that initiated the automatic export. The resource definitions are still marked at other IMS systems as export needed even though the repository is updated, and they will be reset at the next checkpoint at the other IMS systems.

If the resource definitions are cloned, you can specify AUTOEXPORT_IMSID=ALL. This specification is equivalent to using SET(IMSID(*)) on the EXPORT DEFN TARGET(REPO) command.

Note: In an MSC environment, when AUTOEXPORT_IMSID=ALL is specified, the autoexport to the IMSRSC repository will fail if there are any remote transactions or remote transaction descriptors in the list of resource definitions being exported to the repository. The EXPORT DEFN TARGET(REPO) command with the SET(IMSID(imsidlist)) can be used to write the remote transactions and remote transaction descriptors to the repository.

AUTOIMPORT=AUTO | MODBLKS | NO | RDDS | REPO

Specifies whether resource and descriptor definitions are automatically imported during IMS cold start.

The AUTOIMPORT= parameter applies only if dynamic resource definition is enabled.

If dynamic resource definition is enabled for both MODBLKS and MSC resources, the AUTOIMPORT= value applies to both MODBLKS and MSC resources.

If dynamic resource definition is enabled for MODBLKS resources but not for MSC resources, the value specified for the AUTOIMPORT= parameter applies only to the MODBLKS resources and is ignored for the MSC resources. The MSC resources that are generated during an IMS system definition are automatically imported instead.

If dynamic resource definition is disabled for both MODBLKS and MSC resources, the value specified for the AUTOIMPORT= parameter is ignored for both MODBLKS and MSC resources. The MODBLKS and MSC resources that are generated during an IMS system definition are automatically imported instead.

If AUTOIMPORT=AUTO is specified, these conditions determine the source of the imported resource and descriptor definitions:

If all of the following conditions are true, automatic import from the IMSRSC repository is enabled:

• For MODBLKS resources, MODBLKS=DYN is specified to enable MODBLKS DRD in IMS.
• For MSC resources, the MSC section of the DFSDFxxx member of the IMS PROCLIB data set is defined with MSCRSCS=DYN to enable MSC DRD in IMS.
• For MSC resources, the MSC section of the DFSDFxxx member is defined with MSCREPO=Y to enable MSC resources to be stored in the IMSRSC repository.
• The REPOSITORY section of the DFSDFxxx member is defined with TYPE=IMSRSC.
• IMS is enabled with RM services (RMENV=N is not specified in the DFSCGxxx member of the IMS PROCLIB data set or in the CSL section of the DFSDFxxx member of the IMS PROCLIB data set)
• The CSLRIxxx member of the IMS PROCLIB data set is defined for the repository with TYPE=IMSRSC.
• The repository contains stored resource definitions for the IMS system.
• RM is started with the repository enabled.
• The RS address space is started and available.

If all of the following conditions are true, automatic import from an RDDS is enabled:

• MODBLKS=DYN is specified to enable DRD in IMS.
• The REPOSITORY section of the DFSDFxxx member of the IMS PROCLIB data set is not present.
• Two or more system RDDSs are defined in the RDDSDSN() parameter of the DFSDFxxx member of the IMS PROCLIB data set.
• All of the defined RDDSs can be allocated and read.
• At least one of the RDDSs contains valid resource and descriptor definitions.

If all of the following conditions are true, automatic import from the MODBLKS data set is enabled:

• MODBLKS=DYN is specified to enable DRD in IMS.
• The REPOSITORY section of the DFSDFxxx member of the IMS PROCLIB data set is not present.
• No RDDSs are defined in the DFSDFxxx member of the IMS PROCLIB data set, or all the defined RDDSs are empty.
• The MODBLKS data set exists and is not empty.

If all of the following conditions are true, automatic import from the DFSCLL3x member of the IMS.SDFSRESL data set is enabled:

• The REPOSITORY section of the DFSDFxxx member of the IMS PROCLIB data set is not present or the repository does not contain any MSC resources.
• The DFSCLL3x member exists and is not empty.

In addition, only if no errors occur trying to access one or more of the data sets, automatic import is accomplished.

AUTO

IMS determines whether to enable automatic import processing. If IMS enables automatic import, it also determines the data source from which to import the definitions. AUTOIMPORT=AUTO is the default.

IMS chooses as a source for resource definitions the first data source type that it encounters that is enabled for automatic import. IMS searches data sources in the following order:

1. IMSRSC repository
2. RDDS
3. MODBLKS data set and the DFSCLL3x member of the IMS.SDFSRESL data set

If the repository does not contain the stored resource definitions for the IMS, then IMS attempts to read from the RDDS if it is defined and not empty. IMS issues the DFS4405W message if the repository is empty.

If the RDDS is empty, IMS reads from the MODBLKS data set and the DFSCLL3x member of the IMS.SDFSRESL data set if they are not empty. If the MODBLKS data set is empty, IMS comes up with no MODBLKS resources. If the IMS.SDFSRESL DFSCLL3x member does not exist, IMS comes up with no MSC resources.

If the IMS resource list in the repository is not empty, IMS processes the resource definitions returned by the Resource Manager (RM). IMS processes the stored resource definitions from the repository.

If there is an error processing the returned MODBLKS definitions, the action that is taken is based on the IMPORTERR= parameter setting. If IMPORTERR=CONTINUE, IMS marks the MODBLKS resources that are in error with a NOTINIT status and continues processing. If IMPORTERR=ABORT, automatic import processing is canceled, and IMS cold start terminates abnormally with a U3397 abend.

If there is an error reading from the repository, other than if the IMS resource list is not found, a DFS4401E message is issued with the RM return and reason code. Action is taken based on the REPOERR= parameter setting.

MODBLKS

Resource definitions are imported from the MODBLKS data set if one is defined. If definitions are imported from the MODBLKS data set, the values specified for the IMPORTERR=, RDDSERR=, and REPOERR= parameters do not apply and are ignored if specified. If an error occurs, IMS cold start is canceled.

NO

No resource or descriptor definitions are imported when IMS cold starts, if dynamic resource definition is enabled. If dynamic resource definition is not enabled, AUTOIMPORT=NO is ignored.

For MODBLKS resources, AUTOIMPORT=NO applies only if dynamic resource definition for MODBLKS resources is enabled; that is, if the DFSDFxxx <SECTION=COMMON_SERVICE_LAYER> is defined with MODBLKS=DYN. If AUTOIMPORT=NO is defined with MODBLKS=OLC or is defaulted to and MODBLKS resources that are generated from an IMS system definition exist, IMS cold start automatically imports the MODBLKS resources that are generated from the system definition.

For MSC resources, AUTOIMPORT=NO applies only if dynamic resource definition for MSC resources is enabled; that is, if DFSDFxxx <SECTION=MSC> is defined with MSCRSCS=DYN. If AUTOIMPORT=NO is defined with MSCRSCS=NODYN or is defaulted to and MSC resources that are generated from an IMS system definition exist, IMS automatically imports the MSC resources that are generated from the system definition.

RDDS

Resource and descriptor definitions are imported from the most recently updated system resource definition data set (RDDS).

REPO

Stored resource and descriptor definitions are imported (automatic import) from the IMSRSC repository.

If AUTOIMPORT=REPO is specified, the CSLRIxxx member and the REPOSITORY section of the DFSDFxxx member must also be defined with TYPE=IMSRSC.

If the repository does not contain the stored resource definitions for the IMS, then IMS comes up with no resources. IMS issues the DFS4404I message if the repository is empty.

If the IMS resource list in the repository is not empty, IMS processes the resource definitions returned by the RM.

If there is an error processing the returned MODBLKS definitions, the action that is taken is based on the IMPORTERR= parameter setting. If IMPORTERR=CONTINUE, IMS marks the MODBLKS resources that are in error with a NOTINIT status and continues processing. If IMPORTERR=ABORT, automatic import processing is canceled, and IMS cold start terminates abnormally with a U3397 abend.

If there is an error reading from the repository, other than if the IMS resource list is not found, a DFS4401E message is issued with the RM return and reason code. Action is taken based on the REPOERR= parameter setting.

If AUTOIMPORT=REPO is specified and no REPOSITORY section is defined, or the REPOSITORY= statement for the repository is not defined, the DFS4403E message is issued. IMS initialization abends with U0071 with return code X'27'. The DFS2930 message is issued with completion code 27,2108 before the abend.

If AUTOIMPORT=REPO is specified and RMENV=N is specified in the CSL section, IMS initialization abends with U0071 with return code X'27', because IMS cannot access the repository for the stored resource definitions. IMS requires the CSL RM address space to access the repository. The DFS2930 message is issued with completion code 27,210C before the abend.

DCLWA=Y | N

Specifies the default log write ahead option for transactions that are defined with the CREATE TRAN command. DCLWA= specifies whether (Y) or not (N) IMS performs log write-ahead for recoverable nonresponse-mode input messages and transaction output messages. The default is Y. The IMS transaction descriptor DFSDSTR1 is defined with the DCLWA value that was defined in this DFSDFxxx member of the IMS PROCLIB data set. Any subsequent CREATE TRAN commands that are issued either without the LIKE keyword, or with LIKE(DESC(DFSDSTR1)), are defined with this DCLWA value.

Y

Specifies that:

• Information in the log buffers is written to the IMS log before the associated input acknowledgment or output reply is sent to the terminal.
• A nonresponse-input transaction is made recoverable across IMS failures before IMS acknowledges receipt of the input.
• Database changes are made recoverable before IMS sends associated output reply messages.

N

Specifies that input message integrity and the consistency of output messages with associated database updates is not required. DCLWA does not apply to response mode or Fast Path input processing. If it is specified in these situations, is ignored during IMS execution.

IMPORTERR=ABORT | CONTINUE

Specifies which action to take if an error occurs during automatic import processing due to an invalid resource or descriptor definition. This parameter does not pertain to errors that occur while trying to access an RDDS; use the RDDSERR= parameter to choose processing options following RDDS-related errors.

ABORT

Automatic import processing is canceled, and IMS cold start terminates abnormally with a U3397 abend. ABORT is the default.

CONTINUE

Automatic import processing continues. The resource in error is marked and given a not-initiated status (NOTINIT). If the resource is required, create or update the resource after cold start completes.

This value does not apply for MSC resources. If an error occurs during the automatic import of MSC resources, automatic import processing is canceled as if IMPORTERR=ABORT were specified.

RDDSERR=ABORT | NOIMPORT

Specifies which action to take if an error occurs when a resource definition data set is accessed during automatic import processing.

ABORT

Automatic import processing is canceled, and IMS cold start terminates abnormally with a U3368 abend. ABORT is the default.

NOIMPORT

Automatic import processing is canceled. The IMS system is started with no database resources or descriptors (DDIRs), program resources or descriptors (PDIRs), routing code resources or descriptors (RCTEs), or transaction resources or descriptors (SMBs) defined.

RDDSDSN=(dsname1, dsname2,...dsnamen)

Specifies the 1- to 44-character names of the system resource definition data sets. The data sets must be cataloged BSAM data sets. The data sets are dynamically allocated and opened in the order in which they are specified on the RDDSDSN= parm. Each IMS in the IMSplex must have its own set of system resource definition data sets. At least two data set names must be specified. Although any number of data sets can be specified, three RDDSs are recommended. When exporting to a system RDDS, IMS alternates exporting between each of the data sets specified. All resource and descriptor definitions for the local IMS are exported to the oldest data set specified on the RDDSDSN= parameter. When importing from a system RDDS, IMS uses the RDDS with the most current data.

IMS always attempts to write to the RDDS containing the oldest data. If a failure occurs while IMS attempts to write to the data set with the oldest data, the data set with the next oldest data is selected. The RDDS with the most current data is preserved. For example, if two RDDS data sets are defined, and RDDS1 contains the most current resource and descriptor definitions, automatic export attempts to write to RDDS2 first. If that fails, automatic export does not attempt to write to RDDS1. The automatic export function is suspended until the error is resolved.

When creating and allocating the RDDS data sets, be sure to place an end-of-file (EOF) mark at the beginning of the data set. Otherwise, unpredictable results can occur. To ensure that an EOF mark is placed at the beginning of the data set, program IEBGENER can be used with a DUMMY SYSUT1 DD statement that contains the parameters BLKSIZE=xxxxx and RECFM=VB, where xxxxx is a value 4096 - 32760, inclusive. The SYSUT2 DD statement:

• Points to the DSN and VOLSER of the RDDS to be created.
• Specifies LRECL=yyyyy, BLKSIZE=xxxxx, and RECFM=VB, where xxxxx is the value of the block size specified on the DUMMY SYSUT1 DD statement, and yyyyy is (xxxxx − 4).

Recommendation: Set BLKSIZE to 32760.

The RDDSDSN parameter is not required if IMS is defined to use the IMSRSC repository and the repository contains the stored resource definitions for the IMS. If the RDDSDSN= parameter is specified, the RDDS data sets specified is allocated and initialized during IMS initialization.

If AUTOEXPORT=RDDS is specified, an RDDS is used for automatic export processing. If the RDDSs are defined, automatic export to RDDS at system checkpoint is enabled, even if IMS is defined to use the repository.

REPOERR=ABORT | NOIMPORT

Specifies the action to perform if there are errors importing data from an IMSRSC repository that are not due to invalid or missing resource or descriptor definitions. A DFS4401E message is issued with the Resource Manager (RM) request return and reason code.

If there are errors importing data from a repository that are due to invalid or missing resource or descriptor definitions, the IMPORTERR= parameter determines the action to perform.

ABORT

Cancel the IMS cold start if there are errors importing data from a repository. ABORT is the default.

NOIMPORT

Continue the IMS cold start with no resources imported from a repository.