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takeover. That system is the current active, and the information displayed
for the alternate is marked as OLD until a new alternate is signed on and
running normally.
An example of the status display is shown, for guidance purposes, in the CICS
Operations and Utilities Guide.
Note: An ‘X’ following any of these status values indicates that the associated job
is currently executing. However, because JES services are used to discover
the execution state of a job, only those jobs that are running on the same
JES as the overseer program (or on the same JES shared spool) show the
correct execution state. Any job that is not on the same JES shared spool
appears not to be executing.
There are two additional items that may appear on the status display. These are:
v NO ACTIVE DATA
v NO BACKUP DATA.
These are displayed instead of status data when no data was extracted from the
CAVM data sets. This happens when newly-created data sets are used—CICS has
not yet written any data to them—or when the overseer fails to open the data sets.
The restart-in-place function
The overseer program can restart failed CICS regions in place automatically, if they
are in the same MVS image as the overseer. The alternatives to automatic restart
are operator-initiated restart, automatic takeover to the alternate, and
operator-initiated takeover.
Automatic restart in place of failed regions is most useful in the multi-MVS image
MRO environment. Because related regions must operate in the same MVS image,
a takeover of one region means that all related regions must also be taken over by
their alternates. A region may not be important enough for you to want every failure
to cause a takeover to the alternate MVS image. This could disrupt users who
would not otherwise have been affected by the failure. Automatic restart in place of
the failed region is therefore likely to be preferred to takeover in these
circumstances.
If your system consists of one or more independent regions, with actives and
alternates located in separate MVS images, you can:
v Allow the overseer to restart an active region in place automatically when it fails.
v Choose automatic takeover by the alternate.
v Leave the operator to decide what to do. The operator could decide to restart the
failing region in place or to initiate a takeover by the alternate, and this decision
is likely to depend on which part of your system has failed.
If you are operating an MRO system in a single MVS image, the failure of an active
region can be handled by a takeover by the alternate, without causing all the
related regions to be taken over, because the new active region can continue
communication with the other active regions. Takeover is therefore likely to be your
preferred course of action.
Enabling and disabling restart in place: The restart-in-place function of the
overseer program can be enabled and disabled using the Restart command. When
you enter this command, restart processing is enabled or disabled for all generic
applids that the overseer is monitoring. You can also specify that particular
Chapter 26. The extended recovery facility overseer program 691