Secondary index

Every secondary index file must be initialized with a header record having the minimum record length, 76 characters, all set to binary zeroes.

This is a sample of JCL that initializes the header record of a secondary index file. It can be run separately or added to the job that creates the VSAM files. 
//*---------------------------------------------------------------*
//* PREPARE HEADER RECORD
//*---------------------------------------------------------------*
//INIT01   EXEC PGM=SORT
//SYSOUT   DD SYSOUT=*
//SORTIN   DD *
 0       
/*
//SORTOUT  DD DSN=OPCDEV2.RES.SKIHDR,DISP=(NEW,CATLG),UNIT=SYSDA,
              DCB=(RECFM=F,LRECL=76,BLKSIZE=76),SPACE=(TRK,(1))
//DFSPARM  DD *
  RECORD TYPE=F
  SORT FIELDS=(1,1,CH,A)
  OUTREC FIELDS=(76X’00’)
//*---------------------------------------------------------------*
/* INITIALIZE SECONDARY INDEX
//*---------------------------------------------------------------*
//INIT02   EXEC PGM=IDCAMS
//SYSPRINT   DD SYSOUT=*
//SYSIN      DD *
             REPRO INDATASET(OPCDEV2.RES.SKIHDR)-
             OUTDATASET(OPCDEV2.RES.SKI0X)
//*---------------------------------------------------------------*
//* DELETE INPUT FILE
//*---------------------------------------------------------------*
//INIT03   EXEC PGM=IEFBR14
//SORTOUT    DD DSN=OPCDEV2.RES.SKIHDR,DISP=(OLD,DELETE,DELETE)