ASA Database Administration Guide
  Backup and Data Recovery
    Backup and recovery tasks

Recovering from media failure on the database file

The recovery process depends on whether you leave the transaction log untouched on incremental backup in your backup process. If your backup operation deletes or renames the transaction log, you may have to apply changes from several transaction logs. If your backup operation leaves the transaction log untouched, you need to use only the online transaction log in recovery.

For more information about the backup types discussed here, see Designing backup procedures.

To recover from media failure on the database file

1. Make an extra backup copy of the current transaction log. The database file is gone, and the only record of changes since the last backup is in the transaction log.

2. Create a recovery directory to hold the files you use during recovery.

3. Copy the database file from the last full backup to the recovery directory.

4. Apply the transactions held in the backed up transaction logs to the recovery database.

   For each log file, in chronological order,

   • Copy the log file into the recovery directory.

   • Start the database server with the apply transaction log (-a) option, to apply the transaction log:

     dbeng9 db_name.db -a log_name.log

     The database server shuts down automatically once the transactions have been applied.

5. Copy the online transaction log into the recovery directory. Apply the transactions from the online transaction log to the recovery database.

   dbeng9 db_name.db -a db_name.log

6. Perform validity checks on the recovery database.

7. Make a post-recovery backup.

8. Move the database file to the production directory.

9. Allow user access to the production database.