Space announcement We are no longer updating this space, and you cannot comment on this space. The CHANGE ACCUMULATION PLUS component is now documented in BMC AMI Backup and Recovery for IMS.

Output data sets

This section describes how to handle the output data sets that you can use with the BMC Change Accumulation utility. It also explains how to obtain various types of output data sets from the Change Accumulation utility.

Types of output data sets

The Change Accumulation utility can produce the following types of output data sets:

  • The output change accumulation data set is the primary output. Depending on the processing options that you specify, it can be a standard change accumulation data set, a point-in-time (PIT) change accumulation without a specified timestamp, or a PIT change accumulation data set with a specified timestamp (called a timestamp PIT change accumulation data set).
  • If you request the Incremental Image Copy function, you can request creation of one or more output image copy data sets if you have also requested a standard change accumulation or a PIT change accumulation without a specified timestamp. You cannot request output image copy data sets if you have requested a timestamp PIT change accumulation.
  • You can request creation of new log data sets and extract log data sets if you have requested a standard change accumulation. You cannot request these data sets if you have requested a PIT change accumulation.

Dynamic allocation or explicit allocation

You can use dynamic allocation or explicit allocation for output change accumulation and image copy data sets.

Dynamic allocation is recommended because it requires much less work to set up and maintain utility JCL than explicit allocation requires, yet it still provides complete control over allocation parameters. If you do not want the utility to allocate the output data sets dynamically, you can explicitly allocate them by providing DD statements in the job step JCL.

You can use either of the following methods to request dynamic allocation of output change accumulation and image copy data sets:

  • You can create a dynamic allocation model that contains the options that you want to use for allocating the data sets that use this model. You can create as many models as you want. Dynamic allocation models give you the greatest level of control over how the utility allocates the data set.
  • You can specify dynamic allocation options with keywords on function, GROUP, or GLBL control statements. This technique is somewhat less flexible than using dynamic allocation models because you can specify only one set of options that apply to all of the applicable output data sets.

Important

The use of models is a completely separate technique from the use of dynamic allocation keywords on GLBL, GROUP, and function control statements. If you specify the use of a model for a data set, the utility ignores all dynamic allocation keywords that are specified for the data set type on GLBL, GROUP, and function control statements.

Whether you use dynamic allocation or explicit allocation, you use the CA keyword or the STKCA keyword to control the production of output change accumulation data sets. For more information, see Output-change-accumulation-data-set. You use the IC keyword or the STKIC keyword to control the production of output image copy data sets. For more information, see Output-image-copy-data-set.

You must use explicit allocation (with DD statements) for new log and extract log data sets; you cannot use dynamic allocation for these data sets.

Data set names for dynamically allocated output data sets

The utility provides various methods that you can use to determine and control the data set name to be used for an output data set:

  • You can provide a model data set name that contains substitution variables and literal values. The utility resolves these substitution variables and substitutes current values as it dynamically allocates the output data set during execution. This method is available only if you use dynamic allocation models.
  • For change accumulation data sets, you can provide a data set name prefix with the PREF keyword or the CAPREF keyword. For image copy data sets, you can provide a data set name prefix with the PREF keyword or the ICPREF keyword. The utility uses this prefix according to standard rules to build the data set name as it allocates the data set dynamically during execution. This method is available if you use dynamic allocation models or dynamic allocation keywords on function or GROUP control statements.
  • You can use the Data Set Name user exit. This method is available if you use dynamic allocation models (and specify the PREF keyword) or dynamic allocation keywords on function or GROUP control statements.

For more information, see Determining-dynamically-allocated-data-set-names.

Multiple copies

The utility can produce multiple copies (instead of a single copy) of an output data set so that you can use the additional copies for disaster recovery, testing, and other purposes:

  • You can request multiple copies of an output change accumulation data set by specifying a series of values for the CA keyword or STKCA keyword on the GROUP or function control statement or for the DDN keyword on the STACK control statement.
  • You can request multiple copies of an output image copy data set by specifying a series of values for the IC or STKIC keyword on the GROUP or function control statement or for the DDN keyword on the STACK control statement.

The Recovery Extensions feature provides automated management of additional copies of recovery assets. To register additional copies in the Recovery Manager (RMGR) repository, you specify the IRMREG(Y) or IRMREG(R) keyword. To select an additional image copy for input during a Recovery or Incremental Image Copy function, you specify the SIC(n) keyword; n is the number (2-10) of the copy that you want to use. (If you specify copy 2, it is obtained through the DBRC RECONs and the Recovery Extensions feature is not required.) To select an additional change accumulation data set during a Change Accumulation, Recovery, or Incremental Image Copy function, you specify the SCA(n) keyword; n is the number (2-10) of the copy that you want to use.

For more information about the Recovery Extensions feature, see the Using section.

Obtaining multiple copies is explained along with using dynamic allocation and stacking.

Stacked data sets

You can request that the utility write output change accumulation data sets or image copies for multiple database data sets or areas to a single tape volume.

This process is known as stacking. Stacked data sets can help conserve tape volumes and reduce tape mounts. The utility provides several ways for you to control the stacking of output data sets:

  • You can specify the STACK control statement in the control statement data set. This technique provides the finest level of control over the stacking process because you can specify dynamic allocation models for the output data sets. By using the STACK control statement, you can request dynamic allocation of multiple copies of an output data set when one copy is written to a stack and the other copy is not.
  • If you do not use the STACK control statement technique, you can use the keyword technique. To allocate stacked change accumulation data sets, use the STKCA keyword instead of the CA keyword on the function or GROUP control statement. To allocate stacked image copy data sets, you can use the STKIC keyword instead of the IC keyword on the function or GROUP control statement. This technique may be adequate for your purposes but provides little control over the attributes of the stacked data sets.

Important

You cannot use dynamic allocation models with the STKCA or STKIC keyword.

For more information, see Allocating-stacked-data-sets.

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