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Disaster Recovery with BR*ToolsLocate this document in the navigation structure

Use

You can use BR*Tools for Oracle to recover from a disaster. You use BRRECOVER to restore missing or damaged profiles and log files. BRRESTORE is not called by disaster recovery, because it always requires the BRBACKUP Logs or the BRARCHIVE Logs, which might not be available in a disaster.

You use this process if either of the following is true:

  • You have lost the entire database, including the profiles and the BRBACKUP logs or the BRARCHIVE logs.

  • You have only lost the profiles and the BRBACKUP or BRARCHIVE logs.

This process does not actually restore data files or recover redo log files. It only restores the profiles and BRBACKUP or BRARCHIVE logs from copies that you made during previous backups. Therefore, it prepares the database for you to perform one of the following guided BR*Tools options:

Complete database recovery and database PIT recovery are not possible after disaster recovery because the current control file (required for complete database recovery) is missing and the database cannot be opened (required for tablespace PIT recovery).

Caution

Only perform this process if you are an expert in Oracle database administration. Even as an expert, we recommend that you first try other types of recovery supported by BR*Tools.

If you are not an expert, you might severely damage the database with this procedure. You might lose data and cause downtime to fix the problem.

Note

This section discusses how to perform disaster recovery.

For more information on how to approach disaster recovery, see Disaster Recovery.

Prerequisites

  • Since this function is designed for experts, the usual safeguards are not present:

    • There is no database status check.

    • You have less guidance than otherwise, since BRRECOVER does not guide you step by step through restore and recovery.

    • You can choose individual actions independently.

  • For all procedures, the backup medium with the required backup files must obviously be present.

  • You need to know exactly which file to restore and where it is. You are effectively performing a copy at operating-system level.

  • BRRECOVER restores the profiles and logs to the standard directory.

  • If you choose device type Backup utility for the restore, note the following:

    • The BACKINT repository with the latest backup must be available because the tapes are administered using this repository in the backup utility.

    • The BACKINT parameter file must normally exist, depending on the specific implementation that you are using. If it is required but is unavailable, you must first try and recreate it before performing disaster recovery.

    • BRRECOVER calls BACKINT to perform the restore.

    • BACKINT performs the restore from the profiles or logs of the latest backup.

Process

  1. You start BRGUI or BRTOOLS.

  2. You choose Start of the navigation path Restore and recovery Next navigation step Disaster recovery End of the navigation path.

  3. You choose the required procedure:

    • Restore profiles and logs files from BRBACKUP backup

    • Restore profiles and logs files from BRARCHIVE backup

    BRRECOVER starts the restore and displays the menu Device Type.

  4. You choose the device tape where the backups of the profiles or logs are stored.

    BRRECOVER displays the parameters for restoring the profiles or logs, depending on what kind of device type you specified. The default parameters are taken from the current profile, Initialization Profile init<DBSID>.sap, if available.

  5. For a disk backup or a utility backup, you note the following:

    • For a disk backup, you can specify the backup directory. BRRECOVER looks in the sub-directory <DBSID> of the specified directory to find the summary log for BRBACKUP or BRARCHIVE. It uses the information there for the restore.

    • For a utility backup, check Prerequisites above.

  6. You choose Continue to continue the restore with the displayed parameters.

    BRRECOVER warns you that the profiles and logs might be overwritten.

    BRRECOVER displays the restore menu where you can specify which profiles and logs to restore:

    • If a log or profile already exists on disk, the recommendation is No to avoid overwriting it.

    • If a log or profile does not exist on disk, the recommendation is Yes to let you restore it.

  7. If required, you change the recommended values for restoring the profiles and logs. You can select several profiles or logs to restore.

  8. You choose Continue to start restoring the selected profiles or logs.

  9. You check the results in the BRRECOVER logs:

    • The summary log recov<DBSID>.log displays the return code.

    • The detail log v<encoded timestamp>.drv displays the progress.

    For more information on how to view the logs, see Showing Profiles and Logs with BR*Tools.