DFSMSdss: Accommodate new default behavior for full-volume and track restore operations

Description

The data-set-changed indicator (DS1DSCHA) in the VTOC indicates whether or not the data set has changed since its last backup. Before z/OS V2R1, during a full-volume restore operation, DFSMSdss unconditionally reset (turned off) the data-set-changed indicator for each data set restored to the target volume. During a tracks restore operation, if any VTOC track was restored, DFSMSdss might reset the data-set-changed indicator for all data sets on the volume. This applies to all VSAM and non-VSAM data sets and all SMS and non-SMS data sets.

With z/OS V2R1, the default behavior for full-volume and tracks restore operations has changed. By default, DFSMSdss now resets the data-set-changed indicator only if the RESET keyword was specified on the DUMP command. Along with this change, a RESET keyword has been added to the RESTORE FULL and RESTORE TRACKS commands, which allows you to specify whether the data-set-changed indicator is to be reset. In addition, you can use the options installation exit routine, ADRUIXIT, to control the resetting of the data-set-changed indicator.

You can use RESET on the RESTORE command for any FULL or TRACKS dump taken with V2R1, or any previous releases. RESET(YES) and RESET(NO) will work as expected. However, RESET(DUMP) will act as RESET(NO) because there is no way to determine if the RESET keyword was specified at DUMP time on a down-level dump. The new RESET(DUMP) functionality is only available in V2R1.

Note that the default behavior for DFSMSdss DUMP is unchanged when DFSMShsm invokes DFSMSdss to perform a full volume restore. By default, DFSMShsm will pass RESET(YES) to DFSMSdss. The other parameters might be specified through the DEFINE DUMPCLASS command.

Table 1 provides more details about this migration action. Use this information to plan your changes to the system.

Table 1. Information about this migration action
Element or feature:	DFSMSdss.
When change was introduced:	z/OS V2R1.
Applies to migration from:	z/OS V1R13.
Timing:	After the first IPL of z/OS V2R2.
Is the migration action required?	Yes, if you want DFSMSdss to unconditionally reset the data-set-changed indicator during full-volume and tracks restore operations.
Target system hardware requirements:	None.
Target system software requirements:	None.
Other system (coexistence or fallback) requirements:	RESET(DUMP) will act as RESET(NO) because there is no way to determine if the RESET keyword has been specified at DUMP time on a down-level dump. The new RESET(DUMP) function is only available when restoring the dump data set which was taken in V2R2.
Restrictions:	None.
System impacts:	None.
Related IBM Health Checker for z/OS check:	None.

Steps to take

To obtain the behavior in previous releases to allow DFSMSdss to unconditionally reset the data-set-changed indicator during full-volume and tracks restore operations, use RESET(YES) with the RESTORE FULL and RESTORE TRACKS commands. The other options for the RESET keyword are:

NO: DFSMSdss does not alter the DS1DSCHA values. Each DS1DSCHA represents the value the data sets had at the time the dump was taken.
DUMP: DFSMSdss resets the data-set-changed indicator (DS1DSCHA=OFF) only if the RESET keyword was specified on the DUMP command. This is the default.

You can also use the options installation exit routine ADRUIXIT or API programs to override the behavior. The ADRUFO parameter list contains these bits in the UFO8FLGS structure:

UFO8RESY: Corresponds to RESET(YES)
UFO8RESN: Corresponds to RESET(NO)
UFO8RESD: Corresponds to RESET(DUMP).

Note: The default behavior is unchanged when DFSMShsm invokes DFSMSdss to perform a full volume restore. By default, DFSMShsm will pass RESET(YES) to DFSMSdss. You can specify the other parameters through the DEFINE DUMPCLASS command.

Reference information

For more information, see the following references:

For details about the RESTORE command, see
For details about the installation exit, see z/OS DFSMS Installation Exits.
z/OS DFSMSdss Storage Administration.