Restrictions for dynamic resource definition

If you plan to use dynamic resource definition (DRD) in your IMS system, some restrictions apply to your use of DRD.

The following restrictions apply to DRD:

• When DRD for MODBLKS resources is enabled, you cannot perform online change for the resources that are typically defined in the IMS.MODBLKS data set. If you have a simple system, such as a single IMS, and online change meets your requirements, consider continuing to use online change and not enabling DRD.
• In an IMSplex with only one IMS and DRD enabled, the /MODIFY PREPARE MODBLKS and INITIATE OLC PHASE(PREPARE) TYPE(MODBLKS) commands are rejected. The commands /MODIFY PREPARE ALL and INITIATE OLC PHASE(PREPARE) ALL do not apply to the IMS.MODBLKS data set.
• When DRD for MODBLKS and MSC resources is disabled, CREATE, DELETE, IMPORT, and most UPDATE commands that change the definitional attributes of a resource are rejected.

  The following restrictions apply to DRD:

  • You cannot delete IMS-defined internal MSNAMEs, which are MSNAMEs that begin with DFSM, MSNI or MSNS.
  • You cannot delete an IMS-defined shared queues MSNAME that was dynamically created on this back-end IMS because of a CREATE MSNAME command on another IMS in the shared queues group. This MSNAME has a status of SHAREDQ.
• The following parameters for the UPDATE TRAN command are permitted whether or not DRD is enabled:
  • CLASS(class)
  • CPRI(value)
  • LCT(value)
  • LPRI(value)
  • MAXRGN(number)
  • MSNAME(name)
  • NPRI(value)
  • PARLIM(value)
  • PLCT(value)
  • PLCTTIME(value)
  • SEGNO(number)
  • SEGSZ(size)
  • TRANSTAT(Y | N)
• You cannot delete an IMS-supplied descriptor. The only attribute you can update on an IMS-supplied descriptor is the DEFAULT attribute.
• Because of the default Operations Manager (OM) routing in a sysplex, DRD commands are routed to all the IMS systems, unless you specify otherwise. However, the commands are not coordinated across the sysplex, so a command can succeed on some IMS systems and fail on others.
• The Multiple Systems Verification utility (DFSUMSV0) can verify resources defined only by the batch system definition process; it cannot verify resources that were created using DRD. Use the /MSVERIFY command to verify resources that are created dynamically.
• You can update a resource or a descriptor definition, but the changes to that resource or descriptor definition are not propagated to the resource or descriptor definitions that were built from the updated resource or descriptor definition.
• You can import a resource or descriptor from a resource definition data set (RDDS) or the IMSRSC repository and it affects any resource or descriptor explicitly specified in the IMPORT DEFN command, but it does not affect any resources or descriptors built from the specified resource or descriptor.
• DRD commands can be issued only through the OM API.
• DRD commands that work on database resources and descriptors cannot be issued in a DCCTL environment.
• DRD commands that work on transactions and routing code resources and descriptors cannot be issued in a DBCTL environment.
• None of the commands that support DRD can be issued on XRF alternate systems or FDBR regions.
• DELETE DB and UPDATE DB commands are rejected for MSDBs.