Enhancing JCL generation and performance
Out-of-date catalog statistics can adversely affect both the accuracy of the JCL and the time taken to generate it.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.
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. |
To set data set sizing options for a subsystem
- From the BMC AMI Recovery for Db2 Main Menu, select option 4. Subsystem options.
- On the Utility Options Specifications, select 2. Update for Action and for Utility Type 1. Recovery.
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
To set data set sizing options for an object set
- On the BMC AMI Recovery for Db2 Main Menu, select 1. Appl object sets and press Enter.
- On the Object Set List panel, enter a name or pattern and press Enter. A list of object sets is displayed.
- Type S for an object set.
- On the Object Set Edit Panel, select 1. Utility options.
- Select Action 2. Update and for Utility Type 1. Recovery.
- 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.