Limited supportBMC provides limited support for this version of the product. As a result, BMC no longer accepts comments in this space. If you encounter problems with the product version or the space, contact BMC Support.BMC recommends upgrading to the latest version of the product. To see documentation for that version, see BMC AMI Recovery Manager for Db2 13.1.

Enhancing JCL generation and performance

The following sections discuss methods of enhancing JCL generation and performance:

Db2 statistics

To get the best recovery performance, BMC AMI Recovery Manager JCL generation uses the statistics stored in the Db2 catalog.

Out-of-date catalog statistics can adversely affect both the accuracy of the JCL and the time taken to generate it. Use the RUNSTATS utility as often as necessary to keep Db2 catalog statistics current. BMC AMI Copy can be used to update table space level statistics. BMC AMI Recovery Manager also has the option to use the BMCSTATS catalog statistics that are produced by DASD MANAGER PLUS or BMC AMI Copy instead of Db2's catalog statistics.

When to split by partition

When recovering an entire table space, split it by partition when one of the following applies:

  • You made copies by partition and you are using DSNUTILB as the recover utility.
  • You made copies by partition and are requesting multiple job generation. See Multiple-job-optimization.
  • You are using the BMC AMI Recover UNLOADKEYS/BUILDINDEX strategy.

Important

Splitting by partition can increase the time needed to generate JCL.

Data set sizing

For JCL generation, BMC AMI Recovery Manager performs a number of sizing calculations. The following types of data set sizing are performed: 

  • Sort work file sizing for index recovery
  • Image copy sizing for disk copies
  • Work file sizing for CHECK data
  • Table space sizing for multiple job optimization
  • IDCAMS data set allocation size

BMC AMI Recovery Manager uses statistics from the Db2 catalog when available, as well as information from the ICF catalog to size objects. Because sizing calculations can involve a significant amount of Db2 access and processor time, BMC AMI Recovery Manager has options to reduce the use of those resources during JCL generation.

BMC AMI Recovery Manager performs sizing calculations at the time of JCL generation.  

Data set sizing options

The following options are available for the Dataset Sizing field on the General Recovery Options panel.

Option

Description

Catalog

Use the Db2 and ICF catalog information for sizing purposes. This is the default and requires sizing calculations to be performed at the time of JCL generation.

Defaults

Use existing default sizing information from the Work File options established in the Recovery options specification. This option bypasses the sizing calculations by using the primary and secondary space values set in the Work File Options.

BMCSTATS

Use sizing information that is generated when you run BMCSTATS. These statistics are collected by DASD MANAGER PLUS and optionally by BMC AMI Copy.

Important

The IDCAMS data set allocation (performed when you have requested that the VCAT-defined space be deleted and redefined) uses ICF catalog information regardless of the Data Set Sizing option setting. If ICF information is not available, BMC AMI Recovery Manager uses the chosen setting for the Data Set Sizing option.

To set data set sizing options for a subsystem

  1. From the BMC AMI Recovery for Db2 Main Menu, select option 4. Subsystem options.
  2. On the Utility Options Specifications, select 2. Update for Action and for Utility Type 1. Recovery.

  3. On the Update Recover Utility Options Specification panel, select 1. General recovery options and press Enter twice to display the second General Recovery Options panel (the following figure).

    ARMROG02 ====== Browse General Recovery Options SUB SYSTEM DEDL ===============
    Command ===> _________________________________________________________________
                                                                                  
    With defaults and overrides.  Press Enter to continue.                         
                                                                                  
    Lvl (S=System  O=Object Set  Blank=RMGR default)                                    
       Delete STOGROUP objs. . . 2 1. Yes  2. No       (Prior to recovery)        
       REUSE . . . . . . . . . . 2 1. No   2. Yes  3. NOSCR (NOSCR for R+ only)   
       Max concurrent jobs . . . 1_                                               
       Dataset Sizing. . . . . . 1 1. Catalog  2. Defaults 3. BMCSTATS
       Always rebuild indexes. . 2 1. Yes  2. No                                  
       Use INDEX ALL recover . . 2 1. Yes  2. No                                  
                                                                                 
        Mirror Strategy                                                            
         BSDS. . . . . . . . . . _ 1. Both  2. Copy 1  3. Copy 2                  
         Active Logs . . . . . . _ 1. Both  2. Copy 1  3. Copy 2                  
         Catalog and Directory . 2 1. Yes  2. No                                  
         Rmgr Repository . . . . 2 1. Yes  2. No                                  
         Log Master Repository . 2 1. Yes  2. No

    Important

    Although the Data Set Sizing option is located with the General Recovery Options, it is also used when generating backup JCL with any copy utility other than BMC AMI Copy.

To set data set sizing options for an object set

  1. On the BMC AMI Recovery for Db2 Main Menu, select 1. Appl object sets and press Enter.
  2. On the Object Set List panel, enter a name or pattern and press Enter. A list of object sets is displayed.
  3. Type S for an object set.
  4. On the Object Set Edit Panel, select 1. Utility options.
  5. Select for  Action 2. Update and for Utility Type 1. Recovery.
  6. On the Update Recover Utility Options Specification panel, select 1. General recovery options and press Enter twice to display the second General Recovery Options panel.

INDEX ALL recovery

Using the INDEX ALL option can significantly reduce the amount of time required for JCL generation for groups with a large number of indexes (for example, ERP applications such as SAP/R3).

When you select the INDEX ALL option, the ARMBGEN program does not search for indexes that are related to objects in a group during JCL generation because the inclusion of those indexes is implied. Without the INDEX ALL option, the ARMBGEN program searches for indexes related to the objects within the application group and automatically performs data set sizing.

Important

If you use INDEX ALL, you must set the primary and secondary allocations in the work file options for the group.


Warning

Do not use this option if your application group includes indexes or if the group was created by partition because it would cause multiple recoveries of the same index.


Related topics

General-recovery-options

Performance-considerations




 

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