Example: Defining a DFSMShsm environment for SMS-managed tape libraries

For an SMS-managed tape library, many of the management policies for tapes and devices are determined by SMS constructs. These SMS constructs override the unittype parameter of the DFSMShsm commands that control non-SMS tapes and devices. The following table shows the DFSMShsm commands that control tape or device policy and the SMS constructs that override the DFSMShsm commands when tapes are processed in an SMS-managed tape library.

The following commands are simplified because you do not need to provide a unit type with the unittype parameter if you are filtering on a data set name. The storage class and storage group direct a request to a library and the data class controls the device selection.

Function

SMS Construct

DFSMShsm Command

Compact data on tapes

Data class COMPACTION attribute

SETSYS

TAPEHARDWARECOMPACT |
NOTAPEHARDWARECOMPACT

Restrict output to specific devices

Data class MEDIA TYPE attribute

and

Data class RECORDING TECHNOLOGY attribute

ABACKUP agname UNIT(unittype) ARECOVER agname TARGETUNIT(unittype) DEFINE DUMPCLASS(class…UNIT(unittype)) SETSYS

ABARSUNITNAME(unittype)
ARECOVERML2UNITNAME(unittype)
ARECOVERUNITNAME(unittype)
BACKUP(TAPE(unittype))
CDSVERSIONBACKUP
(BACKUPDEVICECATEGORY(TAPE
(UNITNAME(unittype))))
MIGUNITNAME(unittype)
RECYCLEOUTPUT(BACKUP(unittype))
RECYCLEOUTPUT(MIGRATION(unittype))
SPILL(TAPE(unittype))
TAPEMIGRATION(DIRECT(TAPE(unittype)))
TAPEMIGRATION(NONE(ROUTETOTAPE(unittype)))
TAPEMIGRATION(ML2TAPE(TAPE(unittype)))
UNITNAME(unittype)))

TAPECOPY ALTERNATEUNITNAME(unittype1, unittype2) TAPEREPL ALTERNATEUNITNAME(unittype) ALTERNATE3590UNITNAME(unittype1, unittype2)

Figure 1 is an example of the SETSYS commands that define a typical automated tape library (ATL) environment.

Figure 1. Sample Automated Tape Library Environment Definition

/***********************************************************************/
/*  SETSYS COMMANDS IN THE ARCCMDXX PARMLIB MEMBER THAT DEFINE THE     */
/*  DFSMSHSM ENVIRONMENT FOR AN SMS-MANAGED TAPE LIBRARY.              */
/***********************************************************************/
/*
SETSYS DUPLEX(BACKUP MIGRATION)
SETSYS SELECTVOLUME(SCRATCH)
SETSYS PARTIALTAPE(MARKFULL)
SETSYS TAPEDELETION(SCRATCHTAPE)
SETSYS BACKUP(TAPE)
SETSYS TAPEMIGRATION(ML2TAPE)
SETSYS TAPESECURITY(RACFINCLUDE EXPIRATIONINCLUDE)
DEFINE DUMPCLASS(ATLHSM -
       NORESET AUTOREUSE NODATASETRESTORE -
       DISPOSITION('AUTOMATE LOCATION'))
/*

SETSYS DUPLEX

Duplex processing provides an alternative to TAPECOPY processing for backup and migration of cartridge tapes. Duplex processing creates two tapes concurrently; the original tape may be kept onsite while the alternate tape may be either taken offsite or written to a remote tape library. See Creating concurrent tapes for on-site and offsite storage for more information about the DUPLEX keyword.

SETSYS SELECTVOLUME(SCRATCH)

Specifying that DFSMShsm select scratch tapes as the initial tape for dump and as the subsequent tape for dump, migration, and backup is nearly always recommended for SMS-managed tape libraries because libraries are most efficient when they perform nonspecific mounts. See Global scratch pools for more information about nonspecific (global) scratch pools.

SETSYS PARTIALTAPE(MARKFULL)

Migration and backup tapes that are partially filled during tape output processing are marked full. This enables a scratch tape to be selected the next time the same function begins. Marking tapes full enables full exploitation of the cartridge loaders because the cartridge loaders can be filled with scratch tapes between tape processing windows. MARKFULL should be used in a virtual tape environment to improve performance and improve backstore tape utilization.

When the total tape-media use and reducing recycle overhead are more important than cartridge-loader exploitation, PARTIALTAPE(REUSE) can be specified. In a REUSE environment, tapes are fully utilized and the amount of recycle processing is reduced. For more information about the PARTIALTAPE parameter, see Selecting a scratch pool environment.

Because a request to recall a data set can “take away” a migration volume that is currently associated with a migration task, such a partial migration tape is created as if you had specified PARTIALTAPE(REUSE).

SETSYS TAPEDELETION(SCRATCHTAPE)

The SCRATCHTAPE option tells DFSMShsm that recycled migration and backup tapes, along with expired dump tapes, are to be returned to a global scratch pool. You should specify TAPEDELETION(SCRATCHTAPE) when a global scratch pool is in use. For more information about specifying what to do with empty tapes, see Selecting a scratch pool environment.

SETSYS BACKUP(TAPE)

Backup processing is to tape devices.

SETSYS TAPEMIGRATION(ML2TAPE)

The level-2 migration medium is tape. SMS data is directed to level 2 according to its management class. Non-SMS data normally moves to level-1 DASD before migrating to level 2.

SETSYS TAPESECURITY(RACFINCLUDE EXPIRATIONINCLUDE)

Because most sites use a tape management program and because most tape management programs are controlled by expiration dates, many sites require multiple security options to protect tapes. DFSMSrmm does not require the expiration option. For more information about protecting tapes, see Protecting tapes. For more information about DFSMSrmm, refer to z/OS DFSMSrmm Implementation and Customization Guide and "Using DFSMShsm and DFSMSrmm" in z/OS DFSMShsm Storage Administration.

DEFINE DUMPCLASS

The AUTOREUSE option of the DEFINE DUMPCLASS command is especially useful for tape libraries; when dump tapes expire and those dump tapes are associated with a dump class of AUTOREUSE, the tapes are immediately returned to the scratch pool for reuse. If NOAUTOREUSE had been specified, you would have to explicitly DELVOL dump tapes before you could reuse them.