232 IMS Version 8 Implementation Guide
15.7 Inactive subsystems
Online change cannot be done with an inactive IMS in the IMSplex, unless the INIT OLC
PHASE(PREPARE)
command includes either OPTION(FRCNRML) or OPTION(FRCABND).
FRCNRML allows online change to be done even though there are normally terminated IMS
systems within the IMSplex. FRCABND and FRCNRML specified together allow online
change to be done even though there are normally terminated or abended IMS systems
within the IMSplex.
IMS restricts the type of restart that may be done by a system when it was not active during
an online change. This is done to prevent a restart from processing records created with a
different set of libraries than are used by the restart.
Table 15-2 shows the types of restarts that are permitted when an IMS was not active during
the online change. If multiple online changes occur while and IMS is inactive, the inactive IMS
must be cold started (
/NRE CHECKPOINT 0), regardless of the type of online changes made.
Table 15-2 Inactive IMS restart options
IMS restart is not sensitive to changes made in the MFS FORMAT library. So, an online
change only for FORMAT does not restrict the restart. All other online changes require a cold
start of the affected part of IMS. A change to ACBLIB requires a cold start of the database
manager part of IMS. A change to MODBLKS requires a cold start of all of IMS.
15.8 Resource consistency checking
Resource consistency checking may be used to ensure that each IMS system using global
online change is using the same data sets. This capability requires the use of a resource
structure. The checking may be turned off by use of the NORSCCC parameter in the
DFSCGxxx member for an IMS system. Specifying MODBLKS indicates that neither
MODBLKS nor MATRIX data set names will be checked for consistency.
If resource consistency checking is used for ACBLIB, initialization for an IMS system will fail if
it is not using the same ACBLIB data set names that are being used by other members of the
IMSplex which are also invoking consistency checking.
Last online changed type Restart command permitted
ALL /NRE CHECKPOINT 0
MODBLKS /NRE CHECKPOINT 0
ACBLIB /ERE COLDBASE
/NRE CHECKPOINT 0
FORMAT /NRE
/ERE
/ERE COLDCOMM
/ERE COLDBASE
/NRE CHECKPOINT 0

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