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Process documentation Creation of a Logical-Log Backup (ON-Archive)  Locate the document in its SAP Library structure

Purpose

You need to back up the logical log with ON-Archive for use in a restore in the event of database failure. Also, when the logical log is full, the database stops processing. You can use a number of different approaches for the backup.

Prerequisites

You have worked out an approach and met its requirements.

Process Flow

Automatic Logical-Log Backup

With CCMS (recommended by SAP)

  1. You use the DBA Planning Calendar in CCMS to plan your logical-log backups. For more information, see the following:

    2. - If you want to schedule the logical-log backups, see Backing Up the Logical Log in the DBA Planning Calendar (Informix).

    - If you want to trigger the logical-log backups, see Backing Up the Logical Log (Automatic) in the DBA Planning Calendar (Informix).

  2. You make sure the necessary resources (tapes, tape drives, and so on) are available.
  3. You use the archive and backup monitor to check the results.
  4. You check the tapes when the logical-log backup has finished.
  5. You complete the logical-log backup.

Without CCMS (not recommended by SAP)

You decide whether you want to have the logical-log backup triggered using the supplied script logevent.sh or whether you want to enter your own ON-Archive commands to start it:

1. You use the script logevent.sh to specify how full the logical log must be before the logical-log backup is triggered.

2. You make sure the necessary resources (tapes, tape drives, and so on) are available.

3. You check the logical-log backup status if required.

4. You check the tapes when the logical-log backup has finished.

5. You complete the logical-log backup.

Caution

SAP especially recommends you not to rely on starting the backup yourself. The reason is that you have to remember to start it regularly. The danger is that you forget and then the logical log fills up. This might cause the database to stop processing.

1. You make sure the necessary resources (tapes, tape drives, and so on) are available.

2. At the time you choose (for example, 17:00 every day) you enter the ON-Archive command to start the logical-log backup.

3. You check the logical-log backup status if required.

4. You check the tapes when the logical-log backup has finished.

5. You complete the logical-log backup.

Continuous Logical-Log Backup

To Tape

  1. You make sure the necessary resources (tapes, tape drives, and so on) are available.
  2. You enter the ON-Archive command to start the logical-log backup.
  3. You check the logical-log backup status if required.
  4. You check the tapes when the logical-log backup has finished.
  5. You complete the logical-log backup.

Note

When the tape is full, you have to change it, cancel the backup, and start with step 1 again.

For more information, see Performing Continuous Logical-Log Backup to Tape (ON-Archive).

To Disk

  1. You make sure the necessary resources (tapes, tape drives, and so on) are available.
  2. You enter the ON-Archive command to start the logical-log backup.
  3. You check the logical-log backup status if required.
  4. You copy closed save sets to tape, interrupt the backup, and delete the save set on disk before starting from the beginning again.
  5. You check the tapes when the logical-log backup has finished.
  6. You complete the logical-log backup.

Note

When the tape is full, you have to change it, cancel the backup, and start with step 1 again.

For more information, see Performing Continuous Logical-Log Backup to Disk (ON-Archive).

Result

The logical log is backed up. Therefore, you have a copy of logical-log data that can be used for a restore in the event of database failure.

 

See also:

Informix documentation at http://www.informix.com