Initializing the logrec data set

If the logrec data set does not exist, you must first allocate it and then initialize it. (Whenever you allocate or reallocate the logrec data set, the newly allocated data set will not be used until you initialize it and IPL the system on which it is to be used.)

Figure 1 is an example of a job that scratches and uncatalogs an existing logrec data set and allocates, catalogs, and initializes a new one. (If you do not currently have a logrec data set, start with the second step of the job.) Use the JCL statements below to do the following:

Rename the logrec data set. For example, rename SYS1.LOGREC to SYS1.LOGREC.OLD.
Allocate and initialize a new logrec data set with new space specifications using IFCDIP00.

Figure 1. Example: Changing the space allocation

//KATHYLR JOB (9999),'CREATE NEW LOGREC DS',CLASS=A,MSGCLASS=X,
//        MSGLEVEL=(1,1),NOTIFY=KATHY
//*------------------------------------------------------------------
//*  RENAME THE CURRENT LOGREC DATASET
//*  UNCATLG SYS1.LOGREC SO THE NEW LOGREC CAN BE ALLOCATED ON
//*  ANOTHER VOLUME, IF DESIRED
//*------------------------------------------------------------------
//RENAME    EXEC PGM=IEHPROGM
//M43RES    DD VOL=SER=M43RES,UNIT=3390,DISP=SHR
//SYSPRINT  DD SYSOUT=*
//SYSIN     DD *
         RENAME DSNAME=SYS1.LOGREC,VOL=3390=M43RES,                    X
               NEWNAME=SYS1.LOGREC.OLD
         UNCATLG DSNAME=SYS1.LOGREC
/*
//*------------------------------------------------------------------
//*  CREATE THE NEW LOGREC DATASET AND INITIALIZE IT
//*------------------------------------------------------------------
//IFCDIP00 EXEC    PGM=IFCDIP00,COND=(0,LT)
//SERERDS  DD  DSN=SYS1.LOGREC,DISP=(,CATLG),
//         VOL=SER=M43RES,UNIT=SYSDA,SPACE=(CYL,3,,CONTIG)
/*
                                                        //

Note: If you run the JCL in Figure 1 and an error occurs after the logrec data set has been scratched but before it has been reallocated, you will be unable to IPL your system using this logrec data set. To solve this problem, do one of the following:

Use the DFSMSdss stand-alone restore program to restore your old logrec data set.
Run the reallocate job on the data set while running under another system.

See z/OS DFSMSdss Storage Administration for information about the DFSMSdss stand-alone restore program.