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212 VM/HSC 6.0 System Programmer’s Guide
1st ed., 6/30/04 - 312579601
How the BACKup Utility Functions
The BACKup utility performs extensive error checking on CDS records, as well as
comparison checking between primary and secondary copies of the CDS.
Note: In order to run a back up correctly, all data sets currently defined to the HSC should
be specified. This ensures that proper CDS selection and reservation occurs.
If both copies of the data set are available and an I/O error occurs during the analysis
phase of backup, the utility attempts to continue backup on the other copy unless the CDS
keyword specifies the CDS that contains the error. If the CDS keyword specifies the
control data set containing the error, the utility terminates.
Depending upon the option that you select with the keyword OPTion,
• a straight copy is made
• a detailed block analysis is performed
• a restart of the utility is performed.
Copy data sets are made for use as analysis data sets to limit the hardware reserve placed
on the control data set to an absolute minimum. Depending upon options selected, analysis
of data blocks can be performed and block information modified before the data is written
to the backup data set (SLSBKUP).
A return code of eight (RC=8) can be expected if shadowing (a secondary CDS) is enabled
and the secondary /FILE statement is not provided. A backup of the primary control data
set will not be taken.
If for any reason, a return code of eight (RC=8) occurs, the utility may be able to be
restarted (refer to “How to Restart Backup” on page 224).
The RESTore utility works in conjunction with BACKup by formatting the discrepancy
blocks into control card statements and outputting them to the SLSAUDIT data set. When
the HSC is reactivated after a backup and restore, the discrepancy control statements are
input to the SLUADMIN program and AUDIt, UNSCratch, and UNSElect are performed
to resolve discrepancies.
Refer to “Restore Utility” on page 276 for detailed information on the RESTore utility.
Backup