Using change accumulation in a remote site recovery scenario

If you want to periodically create change accumulation data sets and send them for use during forward recovery processing at a remote recovery site, you can consider using change accumulation with the options described in this section.

Up to this point, the process of change accumulation has been described in a way that is mainly suitable for creating change accumulation data sets for use during forward recovery processing at the primary site.

The sample CA job below is an example of running a change accumulation job with options that consolidates all log records found for all VSAM spheres on MVS™ log stream SAMPLE.FWDRECV.LOGSTRM.

The first time this change accumulation job is run, all log records found for all VSAM spheres from the beginning of the log stream, up to the time the job was submitted, are consolidated.

Every subsequent time this job is run, all log records found for all VSAM spheres from the point on the log stream where the previous CA job ended, up to the time the current job was submitted, are consolidated.

The consolidated log records are placed in the change accumulation data set specified in the DWWCA DD statement. See the sections following this example job for a further description of the change accumulation options.

Figure 1. Example CA job with remote site recovery options
 //JOB1 JOB ACCOUNTING INFORMATION,REGION=0M                   1         
 //COMMAND  EXEC PGM=DWWCA                                     2         
 //STEPLIB  DD DSN=DWW.SDWWLOAD,DISP=SHR                       3         
 //DWWCON1  DD DSN=DWW.DWWCON1,DISP=SHR                        4         
 //DWWCON2  DD DSN=DWW.DWWCON2,DISP=SHR                        5         
 //DWWCON3  DD DSN=DWW.DWWCON3,DISP=SHR                        6         
 //DWWMSG   DD SYSOUT=*                                        7         
 //DWWPRINT DD SYSOUT=*                                        8         
 //DWWSORT  DD SYSOUT=*                                        9         
 //SORTWK01 DD UNIT=SYSDA,SPACE=(CYL,(100,25))                 10         
 //SORTWK02 DD UNIT=SYSDA,SPACE=(CYL,(100,25))                 11         
 //SORTWK03 DD UNIT=SYSDA,SPACE=(CYL,(100,25))                 12         
 //DWWCA    DD DSN=SAMPLE.CA.DATASET.ONE,DISP=(NEW,CATLG),     13         
 //            UNIT=3390,VOL=SER=VOLUM1,SPACE=(CYL,(10,10)),              
 //            DCB=(RECFM=VB,LRECL=32752,BLKSIZE=32756)                   
 //DWWIN   DD *                                                14         
    CA GROUP(GROUPONE)       -                                 15        
         ONLY(SAMPLE.FWDRECV.LOGSTRM)                                     
    SPHERE                   -                                 16         
         ALL                                                              
 /*                                                                       
 //
1
The JOB statement defines a CICS® VR job.
2
The EXEC statement defines a CICS VR job step. This specifies that the CICS VR change accumulation program DWWCA is to be run. The prefix DWW always refers to a component of CICS VR.
3
The STEPLIB DD statement specifies the name of the CICS VR load library, for example, DWW.SDWWLOAD, used for this job step.
4 , 5, 6
DWWCON1, DWWCON2 and DWWCON3 define the three CICS VR recovery control data sets. If you are running the CICS VR server, you must use the RCDS naming convention described in Activating the CICS VR server address space.
7
DWWMSG defines the output data set that contains the CICS VR messages. This is usually defined as a SYSOUT data set. The DCB parameters for this data set are RECFM=FBA and LRECL=133. The block size can be provided on the DWWMSG DD statement and must be a multiple of 133. The default is 27930.
8
DWWPRINT defines the output data set that contains the reports produced by CICS VR. This is usually defined as a SYSOUT data set. The DCB parameters for this data set are RECFM=FBA and LRECL=133. The block size can be provided on the DWWPRINT DD statement and must be a multiple of 133. The default is 27930.
9
DWWSORT defines the output data set that contains the CICS VR messages produced during sort processing. This is usually defined as a SYSOUT data set. The DCB parameters for this data set are RECFM=FBA and LRECL=133. The block size can be provided on the DWWSORT DD statement and must be a multiple of 133. The default is 27930.
10 , 11, 12
SORTWK01, SORTWK02 and SORTWK03 define work data sets required by DFSORT.
13
DWWCA defines the output change accumulation data set that contains the consolidated log records. The record format for this data set is RECFM=VB. The record length and block size can be provided on the DWWCA DD statement. The default record length is 32752 and the default block size is 32756.
14
DWWIN defines the data set that contains the CICS VR commands. You can either specify a sequential data set with 80-byte, fixed-length records, or include the CICS VR commands in-stream as shown.
15
On the CA command:
  • The GROUP keyword defines a change accumulation group, GROUPONE.
  • The ONLY keyword specifies that only log records from the portion of log stream SAMPLE.FWDRECV.LOGSTRM read by CICS VR are consolidated.
16
On the SPHERE command:
  • The ALL keyword specifies that all log records for all VSAM spheres found on the portion of the log stream read by CICS VR are consolidated.

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Timestamp icon Last updated: Friday, 29 November 2013


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