ICF Catalog Backup and Recovery: A Practical Guide

Chapter 6. Using Catalog RecoveryPlus 85

6.4.6 Alias processing with BACKUP BCS

If the default keyword, ALIAS, is in effect for the BACKUP command, all related

aliases for the BCS are copied from the current master catalog to the backup

copy at the start of backup for each BCS. If a subsequent RECOVER process is

executed, these aliases are restored to the master catalog on the system running

the RECOVER command. It is also possible to recover ALIASONLY, allowing you

to use this facility to replicate aliases to multiple master catalogs. If, for some

reason, you do not want aliases backed up at all, you can specify NOALIAS on

the BACKUP command.

6.4.7 BACKUP BCS bypasses index processing

The Catalog RecoveryPlus BACKUP command automatically opens the BCS as

a data set. In other words, the Access Method Control Block (ACB) indicates that

we are opening an ICF catalog, but the open process takes place “outside of”

catalog management. The command specifically opens the data component of

the BCS for read access, without using the index. With this logic, BACKUP does

not need to worry about index errors. It reads through the data component of the

BCS in

physical sequential order, deblocking records from the CIs within the

BCS, reblocking them, and writing them out to the backup.

This is unlike most other BCS backup tools, such as EXPORT, which open the

BCS as a catalog – in other words, as a KSDS. If there are corruptions to the

index, the result can be unrecoverable backup failures.

Section 7.1, “Case study #1: Ensuring good backups” on page 113, illustrates the

importance of this logic, where the specific type of BCS corruption resulted in

IDCAMS EXPORT not being able to back up all of the records in the BCS,

whereas the Catalog RecoveryPlus BACKUP backed up the entire BCS. The

difference was specifically due to this processing logic.

6.5 RECOVER command

The Catalog RecoveryPlus RECOVER command provides the ability to restore

or forward recover either part of an ICF catalog, a BCS or a VVDS, from a backup

copy that was created either by IDCAMS EXPORT (BCS only) or the CR+

BACKUP command.

If the backup was created by CR+ BACKUP, the records are first sorted and then

written to the BCS or VVDS being recovered. This logic alerts you (by way of

informational or error messages) to any duplicate key records that are identified.