We recommend using the inner replica facility because you can reference and update the database while making a backup. The following figure shows how to make a backup using the inner replica facility.

Figure D-1 Making a backup using the inner replica facility

Explanation

A backup is made from a replica database, which means that the master database can continue to be referenced and updated while the backup is being made.

When an error occurs in the master database, the backup of the replica database can be used to recover the master database.

For details about the inner replica facility, see the HiRDB Version 9 Staticizer Option Description and User's Guide.

When the inner replica facility is not used

When the inner replica facility is not used, we recommend that you use the updatable mode (-M s specified) to acquire a backup. In such a case, you should make note of the following items:

• The pdcopy command might timeout waiting for a lock-release from an update transaction while a backup is being made. To avoid this situation, either increase the lock-release wait time of the pdcopy command (-j option) or execute the pdcopy command when no update transactions have been issued.
• The database cannot be recovered from the backup alone. The database must be recovered from a synchronization point subsequent to when the backup was made. Therefore, the backup and the system log from the most recent synchronization point subsequent to when the backup was made are required in order to recover the database. When a database is recovered to the most recent synchronization point, the run ID and generation number of the system log file needed for recovering the target RDAREAs is output to the process results output file for the database copy utility. You must manage all subsequent system log files.
  When you recover a database up to the first synchronization point after the backup was made, you must manage the system log files from the last synchronization point before the backup was made to the first synchronization point after the backup was made.