Process flow of the Image Copy function

The following subtopics explain the flow of the Image Copy function processes.

Subtopics:

Image copy process

The following diagram shows the process flow of the Image Copy function.

Figure 1. Process flow of the Image Copy function
This figure depicts the process flow of the Image Copy function. The flow is described in the text that follows the figure.

The process steps match the numbers in the diagram:

  1. User submits the IMS HP Image Copy JCL that specifies the Image Copy function to run.
  2. The Image Copy function reads the DBD library that describes the database data set.
  3. The Image Copy function reads the utility control statements and determines the process.
  4. The Image Copy function reads the database data set.
  5. (Optional) The Image Copy function checks the DBRC RECON data sets.
  6. The Image Copy function creates one or more image copy data sets (compressed if specified as such in the utility control statements.)
  7. The Image Copy function generates outputs that include image copy processing messages, Image Copy Statistics report, DBRC Status report, and optionally, image copy record in the DBRC RECON data sets.

Image copy process with Advanced Image Copy Services

The following diagram shows the process flow for creating image copies with the COPY or the FDUMP option of Advanced Image Copy Services.

Figure 2. Process flow: Image Copy function with Advanced Image Copy Services
This figure depicts the process flow of the Image Copy function with the Advanced Image Copy Services. The flow is described in the text that follows the figure.

The process steps match the numbers in the diagram:

  1. User submits the IMS HP Image Copy JCL that specifies to use Advanced Image Copy Services.
  2. IMS HP Image Copy reads the site default table and ICEIN control statements.
  3. IMS HP Image Copy reads the DBD library and DBRC RECON data sets. These resources contain information about the input database data sets and their status.
  4. Through IMS Tools Online System Interface, IMS HP Image Copy issues IMS commands to prevent transactions and programs from updating the database.
  5. IMS HP Image Copy creates clones of database data sets by using FlashCopy® of Advanced Image Copy Services.
    • If the COPY option is used, the clone data sets become the output image copy data sets.
    • If the FDUMP option is used, the clone data sets are shadow data sets.
  6. Through IMS Tools Online System Interface, IMS HP Image Copy issues IMS commands to bring back the database online. IMS releases the database data sets, and transactions and programs can update the database.
  7. IMS HP Image Copy reads database records from the clone data sets that were created in step 5.
  8. IMS HP Image Copy passes data to the HASH Check program.
  9. If the FDUMP option is specified in the JCL, IMS HP Image Copy creates image copy data sets in standard image copy format.
  10. IMS HP Image Copy registers the image copy data sets to the DBRC RECON data sets.

Image copy process with single-step HASH Check option

The Image Copy function can run HD Pointer Checker HASH Check while it creates an image copy. If you request HASH Check, you need only to take image copies instead of running the HD Pointer Checker utility to verify the pointers of databases. Thus, you can reduce the number of HD Pointer Checker jobs for verifying the pointers of image copies just taken.

To activate the HD Pointer Checker single-step HASH Check option while creating the image copy, run program FABJMAIN enabling the HASH Check option. Both Image Copy and HASH Check processes are run in a single step.

The following diagram shows the process flow of HD Pointer Checker single-step HASH Check within an image copy job of IMS HP Image Copy.

Figure 3. Process flow: Image Copy function with HD Pointer Checker HASH Check
This figure depicts the overview of HD Pointer Checker within an image copy job of IMS HP Image Copy. The flow is described in the text that follows the figure.

The process steps match the numbers in the diagram:

  1. User submits the IMS HP Image Copy JCL that specifies the Image Copy function to run with the single-step HASH Check option.
  2. The Image Copy function reads the DBD library that describes the database data set.
  3. The Image Copy function reads the utility control statements and determines the image copy process and the HASH Check process.
  4. The Image Copy function reads the database data set to take image copies.
  5. (Optional) The Image Copy function checks the DBRC RECON data sets.
  6. The Image Copy function invokes the HASH Check function of HD Pointer Checker.
  7. The HASH Check function checks the database pointers.
  8. The Image Copy function creates one or more image copy data sets.
  9. The Image Copy function and the HASH Check function generate outputs that include Image Copy Statistics report and HD Pointer Checker reports.

Image copy process with multiple-step HASH Check option

With multiple-step HASH Check, the Image Copy function calls the HD Pointer Checker HASH Check process after the image copy is created. This option is useful if you have many data sets to create image copies because the HASH Check can be done to all the data sets within one job step.

The multiple-step HASH Check option needs to be done in three steps:

  1. Run the DBD Analysis program.
  2. Run the Image Copy function with the HASH Check option.
  3. Run the HASH Evaluation program.

The following diagram shows the process flow of using the HD Pointer Checker multiple-step HASH Check option with IMS HP Image Copy.

Figure 4. Process flow: Image Copy function with full-function database multiple-step HASH Check
This figure depicts the overview of the multiple-step full-function database HD Pointer Checker within image copy jobs of IMS HP Image Copy. The process is described in the text that follows the figure.

The process steps match the numbers in the diagram:

  1. User submits the DBD Analysis program JCL.
  2. The DBD Analysis program reads the PSB library.
  3. The DBD Analysis program reads the DBD library.
  4. The DBD Analysis program reads the control statement and determines the process.
  5. The DBD Analysis program generates the DBDEFCTL data set.
  6. The DBD Analysis program issues notification messages.
  7. User submits the IMS HP Image Copy JCL that specifies the Image Copy function to run.
  8. The Image Copy function reads the DBD library.
  9. The Image Copy function reads the utility control statements and determines the image copy process.
  10. The Image Copy function reads the database data sets to take image copies.
  11. (Optional) The Image Copy function checks the DBRC RECON data sets.
  12. The Image Copy function creates one or more image copy data sets.
  13. The Image Copy function generates the reports and messages.
  14. The Image Copy function generates the HASH records.
  15. User submits the HASH Evaluation program JCL.
  16. The HASH Evaluation program reads the DBDEFCTL data set that was created by the DBD Analysis program.
  17. The HASH Evaluation program reads the HASH records.
  18. The HASH Evaluation program generates the Evaluation reports.

Image copy process with DEDB HASH Check option

The Image Copy function can run DEDB Pointer Checker HASH Check while it creates an image copy. If you request HASH Check, you need only to take image copies instead of running DEDB Pointer Checker to verify the pointers of databases. Thus, you can reduce the number of DEDB Pointer Checker jobs for verifying the pointers of image copies just taken.

The following diagram shows the process flow of the DEDB HASH Check option within an image copy job of IMS HP Image Copy.

Figure 5. Process flow: Image Copy function with DEDB HASH Check
This figure depicts the overview of the DEDB HASH Check option within image copy jobs of IMS HP Image Copy. The flow is described in the text that follows the figure.

The process steps match the numbers in the diagram:

  1. User submits the IMS HP Image Copy JCL that specifies the Image Copy function to run with the DEDB HASH Check option.
  2. The Image Copy function reads the DBD library that describes the database data set.
  3. The Image Copy function reads the utility control statements and determines the image copy process and the HASH Check process.
  4. The Image Copy function reads the area data set to take image copies.
  5. (Optional) The Image Copy function checks the DBRC RECON data sets.
  6. The Image Copy function invokes the HASH Check function of DEDB Pointer Checker.
  7. The HASH Check function checks the database pointers.
  8. The Image Copy function creates one or more image copy data sets.
  9. The Image Copy function and the HASH Check function generate outputs that include image copy processing messages, Image Copy Statistics report, and DEDB HASH Evaluation reports.