Multiple object backup support

The multiple object backup support allows you to make a second backup copy of objects based on the object storage group to which the object belongs. You can direct Object Access Method (OAM) to create up to two backup copies of objects using current fields in the SMS management class construct, and by specifying a first and a second Object Backup Storage Group (OBSG) for your object storage groups in the CBROAMxx member of PARMLIB. Additionally, you can direct OAM to write the first and second backup copies on the same removable media type or on different removable media types.

Migration

There are some migration tasks which are required when moving to the z/OS V1R3 release of OAM and you use object backup support. The CBRSMR13 SAMPLIB job must be run if you are migrating from DFSMS/MVS 1.5.0 or OS/390 V2R10 to the current release of DFSMS.

The CBRSMR13 SAMPLIB job contains two jobs that modify the object directories — SMR13A and SMR13B. They require customization before running:

򐂰 SMR13A performs the migration from any DFSMS/MVS 1.5.0 or OS/390 V2R10 system level of the optical configuration database to the z/OS V1R3 version that supports the multiple OBSGs and the second object backup function in the OAM storage management component (OSMC). This job adds a new column BKTYPE to the existing VOLUME table. It also adds a new column BKTYPE to the existing TAPEVOL table. For recovery purposes, we recommend that you create a DB2 image copy of the existing VOLUME and TAPEVOL tables prior to executing this migration job.

򐂰 SMR13B performs the migration from the base version of the OAM object directory tables to the z/OS V1R3 version, which supports second backup copies of objects. This job adds new columns ODBK2LOC and ODBK2SEC to the existing object directory tables. For recovery purposes, we recommend that you create a DB2 image copy of the existing object directory tables prior to running this migration job.

There are also several optional migration tasks. These tasks need only be performed if you intend to exploit the multiple object backup support:

򐂰 Update automatic class selection (ACS) routines to accommodate the new tape data set name of OAM.BACKUP2.DATA. OAM.BACKUP2.DATA is a new tape data set that will be created on OAM tapes that belong to the OBSGs and contain the second backup copies of objects.

You will need to perform this step:

– If you are implementing multiple object backup support and storing second backup copies on tape media

– If the tape is to be SMS managed.

򐂰 Update the SMS management class definition construct to indicate Autobackup is allowed.

Note: After running the CBRSMR13 migration job you may need to run a DB2 reorganization after performing an ALTER to the table.

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򐂰 Update the SMS management class definition construct to indicate the number of backup versions of objects that you want. The field that displays the number of backup versions now displays the number of backup versions to be maintained for objects. The default value for this field is two and any value greater than one is treated as two.

򐂰 Define multiple OBSGs using ISMF.

򐂰 Add the SETOSMC statement to the CBROAMxx member of PARMLIB. Associate at least one OBSG with a SECONDBACKUPGROUP keyword in a SETOSMC statement in order to write a second backup copy of an object. The SETOSMC statement and its associated keywords determines which OBSGs contain the first and second backup copies of the objects that are associated with an object storage group If SETOSMC statements are not provided, OAM will not process second backup copies of objects.

For detailed migration information refer to z/OS V1R3.0 DFSMS OAM Planning, Installation, and Storage Administration Guide Object Support, SC35-0426.

Co-existence

Toleration/coexistence APAR OW47941 is required on all systems which will be running with z/OS 1.3 OAM in the same OAMplex.This APAR introduces several changes:

򐂰 It enables previous releases of OAM to coexist in OAMplex with z/OS V1R3 level.

򐂰 It enables previous releases of OAM to fall back to original version (down to DFSMS 1.4.0).

򐂰 It introduces modified control blocks in OAMplex XCF messages to accommodate different versions of OAM control blocks in OAMplex.

There are OAM messages issued for toleration support on lower level DFSMS systems. Lower level systems will only use a single OBSG but can share the SCDS in OAMplex with a z/OS V1R3 system that has multiple OBSGs defined. When OAM encounters multiple OBSGs defined to a lower level system, the last one defined in the SCDS will be selected for use. OAM will issue message CBR0230D. You can choose to use the last OBSG to contain all backup copies of objects, or specify another is to be used.

If another OBSG is to be used, message CBR0231A will be issued which allows another OBSG name to be used for writing backup copies of objects.

If multiple OBSGs are not defined and no SETOSMC statements are specified in the CBROAMxxx PARMLIB member, OAM will continue to function as it did prior to z/OS V1R3 DFSMS.

If multiple OBSGs are defined but no SETOSMC statements are specified in the CBROAMxx PARMLIB member, OAM will issue CBR0231A to verify which object storage group should be used for backup processing. Second backup copies of objects will not be written.

Changed operator commands

There have been changes made to OAM operator commands in support of the multiple object backup support function in OAM.

򐂰 D SMS,OAM

CBR1100I has been modified to display which backup copy, if any, is being used for Access Backup processing.

򐂰 D SMS,OSMC,TASK(name)

CBR9370I has been modified to show statistics for the number of internal work items queued on the work and wait queues and the number of internal work items completed by the write first and write second backup service during OSMC processing.

򐂰 D SMS,STORGRP(group_name),DETAIL

CBR1130I has been modified to include the names of the first and second backup storage groups associated with this object storage group.

򐂰 D SMS,STORGRP(ALL),DETAIL

CBR1130I has been modified slightly for readability. 򐂰 D SMS,VOLUME(volser)

CBR1140I has been modified for readability and contains a new field to indicate if the volume is used to write first or second backup copies of objects: BACKUP TYPE: (BACKUP1|BACKUP2).

򐂰 F OAM,START,AB,reason[,BACKUP1|BACKUP2]

Syntax modified to allow specification of BACKUP1 or BACKUP2. 򐂰 F OAM,START,RECOVERY,volser[,BACKUP1|,BACKUP2]

Syntax changed to allow optional specification of BACKUP1 or BACKUP2. 򐂰 F OAM,START,OBJRECV,col,obj[,BACKUP1|,BACKUP2]

Syntax changed to allow optional specification of BACKUP1 or BACKUP2. New OAM commands

There is a new operator command to display the current SETOSMC global settings and by storage group. The backup storage group can be specified at both the global and the storage group level:

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CBR1075I GLOBAL VALUE FOR BACKUP1 IS backup1 CBR1075I GLOBAL VALUE FOR BACKUP2 IS backup2 򐂰 F OAM,DISPLAY,SETOSMC,group-name

CBR1075I group_name VALUE FOR BACKUP1 IS backup1 CBR1075I group_name VALUE FOR BACKUP2 IS backup2

Changed CBROAMxx PARMLIB options

New parameters have been added to the SETOSMC and the SETOSMC STORAGEGROUP statements.

This is the SETOSMC syntax:

SETOSMC FIRSTBACKUPGROUP(global_1st_bu_group) SETOSMC SECONDBACKUPGROUP(global_2nd_bu_group)

These keywords specify the default first and second backup storage groups at the global level. They will be used as the default OBSGs when both of the following are true:

򐂰 The object storage group to which the object is defined is not specified in the on the SETOSMC statement FIRSTBACKUPGROUP and

SECONDBACKUPGROUP parameters

򐂰 The management class that is assigned to the object specifies that a first or second backup copy can be written.

SETOSMC STORAGEGROUP(obj_storage_group FIRSTBACKUPGROUP(1st_bu_group)) SETOSMC STORAGEGROUP(obj_storage_group SECONDBACKUPGROUP(2nd_bu_group))

If no second backup group is defined, either globally or on a specific object storage group, then no second backup copy will be taken regardless of the settings in the management class.

Multiple object backup scenarios

Here we present three scenarios which explain what backups are taken, based on the management class setting and the SETOSMC statements.

Keep in mind that an object storage group can be made up of objects that have different management classes, and therefore can have different numbers of backup versions assigned to them. This will affect how they are treated during OSMC processing. For the sake of simplicity, in the following scenarios all objects in an object storage group have the same management class assigned. Scenario one

Auto Backup = ‘Y’

Number of Backup Versions = 2

CBROAMxx PARMLIB settings:

SETOSMC STORAGEGROUP(GROUP22 FIRSTBACKUPGROUP(BACK00A) - SECONDBACKUPGROUP(BACK00B))

SETOSMC STORAGEGROUP(GROUP44 FIRSTBACKUPGROUP(BACK00A))

Results of running the OAM space management cycle (OSMC): GROUP22 object — two backup copies successfully written

GROUP44 object — fails (x'0472') attempting to write second backup

Scenario two

Management class settings:

Auto Backup = ‘Y’

Number of Backup Versions = 2

CBROAMxx PARMLIB settings:

SETOSMC STORAGEGROUP(GROUP22 FIRSTBACKUPGROUP(BACK00A)) SETOSMC STORAGEGROUP(GROUP44 FIRSTBACKUPGROUP(BACK00A))

Results of running OSMC cycle

1 backup copy written for GROUP22 and GROUP44 objects

Scenario three

Management class settings:

Auto Backup = 'Y'

Number of Backup Versions = 1

CBROAMxx PARMLIB settings:

SETOSMC STORAGEGROUP(GROUP22 FIRSTBACKUPGROUP(BACK00A) - SECONDBACKUPGROUP(BACK00B))

Note: In this scenario, because one of the storage groups has a second backup group defined and the number of backup versions is set to two, two backups will be attempted for all storage groups but will only succeed for storage groups with the SECONDBACKUPGROUP parameter specified.

Note: In this scenario, there is only one backup copy taken, even though the number of backup versions is set to two in the management class. No storage group has a SECONDBACKUPGROUP parameter specified in the SETOSMC statement.

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SETOSMC STORAGEGROUP(GROUP44 FIRSTBACKUPGROUP(BACK00A) - SECONDBACKUPGROUP(BACK00B))

Results of running OSMC cycle

1 backup copy written for GROUP22 and GROUP44 objects

As you can see from these scenarios, if you have SECONDBACKUPGROUP

parameters specified on the SETOSMC statement in the CBROAMxx PARMLIB member, OSMC will attempt to create a second backup copy for any objects that have a Management Class with Autobackup and Number of Backup Versions greater than 1 (the default is 2). If you don't want a second backup copy attempted then you need to change Number of Backup Versions in the your existing Management Class constructs.

Application programmer interface (API) changes

The OAM API has been updated to include support for the multiple object backup feature. The OAM API is referred to as OSREQ:

򐂰 OSREQ RETRIEVE has been modified to allow direct retrieval of second backup copy using VIEW=BACKUP2.

򐂰 OSREQ TSO command interface has been modified to allow direct retrieval of second backup copy using VIEW(BACKUP2) parameter.

򐂰 OSREQ QUERY has been modified to add a Backup2 retrieval order key. This field can be used to sort objects prior to issuing retrievals for most efficient mount and media positioning time.