Process documentationRestore and Application of Offline Redo Log Files with BR*Tools

 

You can use BR*Tools for Oracle to restore and apply offline redo log files – that is, archivelog files. BRRESTORE restores offline redo log files and BRRECOVER applies the offline redo log files.

Caution Caution

Only perform this procedure 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.

End of the caution.

Note Note

This section discusses how to perform a restore and apply of offline redo log files.

For more information about how to approach restore and apply of offline redo log files, see Restore and Application of Offline Redo Log Files.

End of the note.

Prerequisites

  • Make sure you have set the necessary BRRECOVER parameters in the initialization profile init<DBSID>.sap, because BRTOOLS uses these when it calls BRRECOVER.

  • 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.

    • The database is closed for the shortest time possible.

    • You can overwrite existing offline redo log files if required.

  • You must meet the following prerequisites before starting the restore or apply:

    Procedure

    Requirements

    Restore archivelog files

    • Check that there is enough free space in the restore directory

    • The BRARCHIVE summary log exists

    Apply archivelog files

    Identify the offline redo log sequence number that the database requires to start the apply.

    Open database

    Make sure that all database files are consistent before trying to open the database.

  • BRRECOVER calls SQLPLUS to apply the offline redo log files.

  • For Apply archivelog files, you can force application of the online redo logs – that is, the online redo logs that have been archived but not yet overwritten.

Process

  1. You start BRGUI or BRTOOLS.

  2. You choose Start of the navigation path Restore and recovery Next navigation step Restore and application of archivelog files End of the navigation path.

  3. You choose the required procedure.

    BRRECOVER starts the restore or apply.

  4. If you chose Restore archivelog files, you set the required options and choose Continue to start the restore

    Menu Entry

    Equivalent BRRESTORE Command Options

    BRRESTORE profile (profile)

    -p|-profile

    Instance of archivelog thread (instance)

    Oracle Real Application Cluster (RAC) only

    -a|-archive <DBSID>

    First sequence number (first_seq)

    -a|-archive <log_no1>-<log_no2>

    Last sequence number (last_seq)

    -a|-archive <log_no1>-<log_no2>

    Restore device type (device)

    -d|-device

    BACKINT/Mount profile (parfile)

    -r|-parfile

    Database user/password (user)

    -u|-user

    Restore second copy (sec_copy)

    -a2|-archive2

    Destination directory (dest_dir)

    -a|-archive <log_no1>-<log_no2> rest_dir

    Confirmation mode (confirm)

    -c|-confirm

    Query mode (query)

    -q|-query

    Compression mode (compress)

    -k|-compress

    Additional output (output)

    -o|-output

    Message language (language)

    -l|-language

    BRRESTORE command line (command)

    This shows you the BRRESTORE command that is to be executed using the current settings.

    Note Note

    Restore device type (device) is taken from the device type used for the backup containing the selected offline redo log files.

    All selected offline redo log files must be backed up on the same backup device type.

    Restore second copy (sec_copy) lets you use the second copy of the restore if the first is damaged or unavailable.

    End of the note.

  5. If you chose Apply archivelog files, you set the required options and choose Continue to start the apply:

    Menu Entry

    Meaning

    Archivelog directory (archive_dir)

    The source directory used by SQLPLUS to apply the redo log files

    Instance of archivelog thread (instance)

    Database instance that created the offline redo log files

    Apply from online redolog (apply_redo)

    Apply changes recorded in the online redo log

    First sequence number (first_seq)

    The sequence number of the first redo log file to apply

    Last sequence number (last_seq)

    The sequence number of the last redo log file to apply

    Last system change number (last_scn)

    Specifies that the recovery finishes with an Oracle system change number (SCN)

    End point-in-time (end_pit)

    Specifies that the recovery finishes with a normal point in time, using the time stamp (that is, date, hours, minutes, and seconds)

    Use backup control file (back_ctl)

    Option for SQLPLUS RECOVER command

    Parallel recovery (degree)

    Specifies whether the recovery is serial or parallel

    SQLPLUS command (command)

    This shows you the SQLPLUS command that is to be executed using the current settings.

    Note Note

    You must enter First sequence number (first_seq) and Last sequence number (last_seq). In this case, all the offline redo logs in the sequence you specify are applied. If required, you can also enter Last system change number (last_scn) or End point-in-time (end_pit). In this case, only changes in the logs up till the last_scn or end_pit that you specify are applied.

    End of the note.

  6. If you chose Open database, you open the database.

  7. You check the results in the BRRECOVER and BRRESTORE logs:

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