Defining SETSYS parameters for aggregate recovery

The SETSYS command allows you to externally define various aggregate recovery environmental options.

To ensure that the settings are defined to DFSMShsm at startup initialization, the system programmer should include the SETSYS command in the DFSMShsm parmlib member (ARCCMDxx). If you are an authorized DFSMShsm user, you can issue the SETSYS command before an aggregate recovery to modify the SETSYS parameters that control aggregate processing.

To specify how many ABARS commands can run concurrently, use the MAXABARSADDRESSSPACE parameter. MAXABARSADDRESSSPACE specifies the maximum number of concurrent ABARS secondary address spaces that DFSMShsm supports (up to 64). When determining the value to specify for MAXABARSADDRESSSPACE, factor in such items as system load, resource contention, aggregate backup and recovery activity. The overriding factor is the number of tape drives available (the default for MAXABARSADDRESSSPACE is 1).

When an ARECOVER command completes, ABARS determines if there is another ABARS request queued that has not been processed. If there is, DFSMShsm reuses the address space to process that command. The address space remains active until there are no further ABARS commands queued, or the SETSYS MAXABARSADDRESSSPACE command has reduced the number of ABARS address spaces and this address space is no longer required.

The tape unit type used for the control and data file must be compatible with the tape unit type used during aggregate backup. You will specify this unit type later as part of the UNIT parameter of the ARECOVER command or in the SETSYS ABARSUNITNAME parameter.

The ABARSPROCNAME parameter specifies the procedure name used to start an ABARS secondary address space when no such address space is available for reuse. The default is DFHSMABR.

The EXITON(exitname) parameter lets you specify which installation exits (ARCCREXT, ARCSKEXT, ARCTVEXT) are active during aggregate recovery processing.

The OPTIMUMDASDBLOCKING parameter allows efficient utilization of DASD when ABARS performs aggregate recovery at your recovery site. When ARECOVER recovers a data set to ML1 DASD and SETSYS OPTIMUMDASDBLOCKING has been specified, ARECOVER determines the maximum block size for the data set on the ML1 DASD. This information is used for the allocation block size of the migrated data set. The 2K records of the input migrated data set are reblocked to the optimum block size for the output data set.

If SETSYS NOOPTIMUMDASDBLOCKING is specified, DFSMShsm does not define optimum block size for the output data set.

The ARECOVERUNITNAME parameter specifies a default tape unit name for user tape data sets being recovered to a tape unit during recovery processing. If the TARGETUNIT parameter of the ARECOVER command is specified, its value takes precedence over any value specified for the ARECOVERUNITNAME parameter. However, if neither parameter is specified, a default of 3590-1 is assumed. This parameter can be overridden if SMS is active and ACS routines assign a tape storage group to the data set.

The ABARSVOLCOUNT(NONE | ANY) command allows you to affect the method of invoking DFSMSdss for restoring L0 data sets that were dumped from primary volumes. If NONE is specified, the DFSMSdss VOLCOUNT parameter is not passed to DFSMSdss during the restore. If ANY is specified, the VOLCOUNT(ANY) parameter is passed to DFSMSdss during the restore. Specifying VOLCOUNT(ANY) to DFSMSdss results in the allocation of the target data set on as many volumes as required, up to a maximum of 59 volumes.

The ARECOVERPERCENTUTILIZED(nnn) parameter allows you to specify to what percent DFSMShsm allows DFSMSdss to fill non-SMS DASD recovery volumes during any ARECOVER command processing. For nnn, substitute an integer number between 1 and 100. The default is 080 (80%).

Tip: When you issue any ARECOVER command, you can temporarily override the SETSYS ARECOVERPERCENTUTILIZED value by using the PERCENTUTILIZED parameter of the ARECOVER command.

Each time you issue the ARECOVER command, an activity log is created. You can use the SETSYS ABARSACTLOGTYPE parameter to specify whether you want the activity log automatically written to SYSOUT or to DASD. You can use the SETSYS ABARSDELETEACTIVITY(Y | N) command to specify whether you want DFSMShsm to automatically delete the ABARS activity log that corresponds to the ABACKUP version being rolled off. The deletion occurs during ABARS roll-off processing or EXPIREBV ABARSVERSIONS processing, and removes the need to manually manage the ABARS activity logs.

The default, if you do not specify the SETSYS ABARSTAPES command, is the STACK option.

When SETSYS ABARSTAPES(STACK) is specified, ARECOVER attempts to process the ABACKUP output files as if they are stacked. If the files are not stacked, ARECOVER detects the error and attempts to process the files as if ARECOVER were issued with the NOSTACK option. When SETSYS ABARSTAPES(NOSTACK) is specified, ARECOVER attempts to process the ABACKUP output files as if they are not stacked. If the files are stacked, ARECOVER detects the error and attempts to process the files as if ARECOVER were issued with the NOSTACK option.

Specifying the XMIT parameter with the ARECOVER command when using stacked output tapes has the following effect on ARECOVER processing:

ARECOVER relies on information in the catalog to determine the file sequence numbers during the allocation of ABACKUP files. If the ABACKUP files, with the exception of the control file, are not cataloged, ARECOVER obtains the file sequence numbers from the control file.
XMIT processing for STACKED output remains basically the same as for data that is not stacked, meaning that deallocation and allocation occur for each ABACKUP file processed. This can result in several mount requests for the same tape volume.
If the ABACKUP output is transmitted, it is possible for the data to be received on a device type and geometry different from that on which it was originally written. Because of this, you cannot assume that the files will still be stacked when received by the network transmission software.

ABARS records the CPU time for processing ARECOVER requests, along with any applicable account code information. This information is written to the ABR record and can be obtained using the LIST AGGREGATE command. This information is written to the FSR control block. The FSR can be written as an SMF record if the installation specifies SETSYS SMF(smfid). ABARS then writes the FSR as smfid + 1 in the SYS1.MANx or SYS1.MANy system data sets. Installations can use the information to calculate charge backs for ABARS requests.

The new SETSYS ARECOVERTGTGDS(option) command provides greater flexibility for managing SMS-managed generation data sets that are being restored to level 0 DASD. You can specify the following options:

DEFERRED: Specifies that the target data set is to be assigned the DEFERRED status.
ACTIVE: Specifies that the target data set is to be assigned the ACTIVE status, for example, rolled into the GDG base.
ROLLEDOFF: Specifies that the target data set is to be assigned the ROLLEDOFF status.
SOURCE: Specifies that the target data set is to be assigned the same status it had when it was backed up.

The default option is SOURCE, which is consistent with prior releases of DFSMShsm.

Installations are able to override the SETSYS ARECOVERTGTGDS(option) specification with a new ARECOVER command TGTGDS(option) keyword parameter. The options for ARECOVER TGTGDS are the same options as for SETSYS ARECOVERTGTGDS.

Note: If the SETSYS DEBUG parameter is specified before aggregate recovery processing, DFSMShsm does not move any data. DEBUG causes all ARECOVER commands to be processed as if the VERIFY option is specified.

Defining SETSYS parameters for aggregate recovery

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