Controlling the next restart (CRESTART) on z/OS

We can use the CRESTART function of CSQJU003 to control the next restart of the queue manager, either by creating a new conditional restart control record or by canceling the one currently active.

These records limit the scope of the log data used during restart (truncating the log, in effect) . Any existing conditional restart control record governs every restart until one of these events occurs:

  • A restart operation completes
  • A CRESTART CANCEL is issued
  • A new conditional restart control record is created
Attention: This can override IBM MQ efforts to maintain data in a consistent state. Only use this function when implementing the disaster recovery process described in Recovering a single queue manager at an alternative site and Recovering a queue sharing group at the alternative site, or under the guidance of IBM service.

CRESTART

CRESTART CREATE,ENDRBA=endrba,ENDLRSN=endlrsnCANCEL


Keywords and parameters

    CREATE
    Creates a new conditional restart control record. When the new record is created, the previous control record becomes inactive.
    CANCEL
    Makes the currently active conditional restart control record inactive. The record remains in the BSDS as historical information.

    No other keyword can be used with CANCEL.

    ENDRBA= endrba
    Gives the last RBA of the log to be used during restart (the point at which the log is to be truncated), and the starting RBA of the next active log to be written after restart. Any log information in the bootstrap data set and the active logs, with an RBA greater than endrba, is discarded.

    endrba is a hexadecimal number of up to 16 digits. If we use fewer than 16 digits, leading zeros are added.

    The value of ENDRBA must be a multiple of 4096. (The hexadecimal value must end in 000.)

    A value higher than FFFFFFFFF000 cannot be specified for a version 1 format BSDS.

    ENDLRSN= endlrsn
    Gives the LRSN of the last log record to be used during restart (the point at which the log is to be truncated). Any log information in the bootstrap data set and the active logs with an LRSN greater than endlrsn is discarded.