StorageTek Host Software Component 6.0, System Programmer'S Manual

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60 VM/HSC 6.0 System Programmer’s Guide
1st ed., 6/30/04 - 312579601
Dynamic Enable/Disable of Control Data Sets
Operator commands are supplied to give you control over which data sets the HSC is
utilizing. This functionality is particularly useful in a multiple-processor environment.
Before attempting to enable or disable any data set, you can use the Display CDS
command to display the current status of the control data sets.
The commands to enable or disable a control data set can be issued without halting HSC
execution or disrupting any running HSC.
Refer to Chapter 2, ‘‘Commands, Control Statements, and Utilities’’ in the HSC
Operator’s Guide for detailed information about operator commands for enabling or
disabling control data sets.
Reassigning Control Data Set Names in Database Heartbeat Record
The names of the control data sets are recorded by the HSC in the Database Heartbeat
(DHB) record to identify the correct primary, secondary and standby control data sets.
When HSC is initialized, it assigns its control data set copies as primary, secondary and
standby based on the Database Heartbeat record, not on the assignment in the CDSDEF
PARMLIB statement.
When HSC systems are running, the assignment of specific control data sets as primary,
secondary and standby happens automatically and is not normally of concern.
Either of the following procedures can be used to change the assignment of control data
sets as primary, secondary and standby in the Database Heartbeat record.
• Procedure using CDS Disable and CDS Enable commands:
1. Use CDS Disable and CDS Enable commands to rotate the control data sets into
the desired sequence.
2. Use the Display CDS command to view the current status and assignment of the
control data sets.
For example, to switch the assigned order of a primary control data set (with
DSN=SLS.DBASE1
) and a secondary control data set (with
DSN=SLS.DBASE2
):
1. Issue the command:
to view the current control data set status and assignments.
2. Make the current secondary control data set the new primary control data set by
issuing the command:
DISPLAY CDS
CDS DISABLE PRIMARY