Log control with DBRC

Database Recovery Control (DBRC) assists you in controlling DBCTL logs and in managing recovery of databases. With DBCTL, you must use DBRC to control DBCTL logs, and you may optionally use it to control batch logs and database recovery.

DBRC places the information it uses to control recovery in the RECON data sets, which are required with DBCTL. These data sets include information about the OLDS; for example, it indicates whether an OLDS is available for use or contains data that must be archived.

Define three RECON data sets when you install DBRC. Two of the RECON data sets are active; the third is a spare. For most purposes, you can think of the two active RECON data sets as a single RECON data set, or the RECON.

DBCTL requires DBRC to be at SHARECTL level; if it is not, DBCTL will not start. To initialize the RECON specify (or let it default to) INIT.RECON SHARECTL. Figure 1 shows some example JCL you can copy to initialize the RECON.

Figure 1. Example JCL to initialize the RECON

//INITREC JOB 1,PGMERID,CLASS=Q,MSGCLASS=A
//*
//RECON    EXEC PGM=DSPURX00,REGION=1000K
//STEPLIB  DD DSN=IMS.RESLIB,DISP=SHR
//DFSRESLB DD DSN=IMS.RESLIB,DISP=SHR
//SYSPRINT DD SYSOUT=*
//RECON1   DD DSN=IMS.RECON1,DISP=SHR
//RECON2   DD DSN=IMS.RECON2,DISP=SHR
//SYSIN    DD *
 INIT.RECON SSID(IMSA)
/*

If you already have a RECON, specify (or let it default to) CHANGE.RECON SHARECTL. When the OLDS is full, DBRC starts a log archive job. Skeleton JCL statements are edited by DBRC before the job is submitted. The skeleton JCL is member ARCHJCL of the library specified in the JCLPDS DD statement in the DBRC JCL. You do not have to wait for the OLDS to fill in order to test the automatic log archive. Instead, you can cause the OLDS to switch using the DBCTL operator command /SWITCH OLDS. Alternatively, you can use the /DBRECOVERY without the NOFEOV keyword. For guidance on the syntax of the /SWITCH and /DBRECOVERY commands, see Operations and automation in IMS product documentation. (See also Operator communication with DBCTL: overview for information on using DBCTL operator commands.)

For detailed guidance on automatic log archiving and DBRC skeleton JCL, see Database utilities in IMS product documentation. For further guidance on using DBRC, see Operations and automation in IMS product documentation.