Backup Procedures

Perform Backups Often

Backup procedures are an essential part of database administration. To help protect the integrity of your database, you should perform backups as often as possible. As a general rule, always back up the database:

At regular, scheduled intervals, such as daily or weekly
Before and after structural changes to the database
Whenever you initialize journal files
Since automatic recovery is not available in local mode, before and after executing an application run in local mode.

Design a Backup Plan

To ensure that your backup procedures meet the data processing needs of your company, you need to decide how often to take backups and how long to retain them. Develop a schedule and procedures for performing backups and stick to it.

General Guidelines

The following list identifies some guidelines to follow in designing a backup plan:

Define the backup and recovery requirements for an application while the application is being designed. Test all backup and recovery procedures before the application is put into production.
Make sure you backup the database after making changes to its physical definition (such as changing the page size, page range, and so on).
Identify all archive files created since the last backup.
If you need to concatenate archive tapes for historical records, make sure that the tapes included in the concatenation are not required for recovering the database. For example, you might concatenate the archive tapes from the previous week at the end of the current week.
Bear in mind that restoring a database from a date several weeks in the past can be a very time-consuming process because of the volume of journal data that needs to be processed.

BACKUP Utility Statement

The examples outlined in this chapter use the BACKUP utility statement provided with CA IDMS/DB to backup the database. You can use other utilities (such as IEBGENER in z/OS) to perform the backup and recovery operation provided they restore disk files to the state they were in when copied.

If you use the CA-provided BACKUP utility statement for regularly scheduled backups, specify the FILE option rather than the AREA option. FILE lets you recover an individual file in the event it is damaged rather than having to recover the entire area. Use the AREA option only if multiple areas are stored in a single file.