Generating recovery JCL
You can use either the GENJCL.RECOV command or the /RMGENJCL command to generate the JCL that is necessary to recover a registered database data set.
Procedure
- Selects the image copy data set to use for loading the most recent image copy
- Selects the change accumulation and log data sets that are to be input to apply all the changes that were logged since the image copy was created
If change accumulation input is required (because of data sharing), but it is not present or usable, DBRC informs you of that fact and the GENJCL.RECOV command fails.
The GENJCL.USER command can generate user-defined output, which can include JCL. No skeletal JCL execution members are supplied to support the GENJCL.USER command. If you want to enter GENJCL.USER commands, you must supply the members to support them.
When you issue either the GENJCL command or the /RMGENJCL command, DBRC reads skeletal JCL and replaces symbolic parameters with actual values based on the information recorded in the RECON data set to build the appropriate JCL. For example, if you request that DBRC generate JCL to recover a database, DBRC retrieves the skeletal JCL member from the library and completes the JCL with information about the latest image copy, change accumulation, and log data sets, if necessary. Your databases must be registered in order for DBRC to generate JCL to process them.
The amount of time and effort required to recover a database can be significantly reduced by using the GENJCL command to generate the JCL and control statements necessary for the recovery. Using the GENJCL command also eliminate the causes of many recovery errors. You could spend a large amount of time during database recoveries determining which input data sets should be provided in what order to the Database Recovery utility.
When change accumulation data sets or PRILOG records (in the RECON data set) are available, DBRC selects them rather than the SLDS for recovery. This results in quicker database recoveries if you run the Database Change Accumulation regularly. DBRC knows which log data sets are required and ensures that IMS processes all volumes in the correct order. DBRC also selects the most recent image copy for database recovery.
DBRC always selects the optimum input for the Database Recovery utility by using change accumulation data sets whenever possible. If you have not used the Database Change Accumulation utility, or if that utility did not process some log data sets, DBRC selects the required log data sets from the PRILOG (or SECLOG) records, which can contain RLDS, SLDS, or both RLDS and SLDS entries.
- See IMS Version 15.5 System Definition for more information about the tailoring actions for IMS PROCLIB members, the DBRC procedure, and the JCLOUT and JCLPDS DD statements.
- See IMS Version 15.5 Commands, Volume 3: IMS Component and z/OS® Commands for details about customizing your own skeletal JCL and about the contents of IMS-supplied skeletal JCL.