6 Backing Up and Recovering a Database

Using BS2000 Utilities to Back Up an Oracle Database

You can back up an Oracle database using BS2000 operating system utilities (for example, ARCHIVE or the /COPY-FILE command).

Use the following steps to back up an Oracle database:

1. While the database is running, collect the names of all files, which make up the Oracle database. You can determine the names of the log and database files by entering the following commands:

   /START-PROGRAM $ORAC1020.SQLPLUS
   * /NOLOG
   SQL> CONNECT / AS SYSDBA
   SQL> SELECT * FROM V$DATAFILE;
   SQL> SELECT * FROM V$LOGFILE;
   

2. To ensure that all Oracle database files are synchronized at the time of the backup, shut down the Oracle database using SQL*Plus.

3. Back up all database files and log files using the BS2000 ARCHIVE utility or the BS2000 /COPY-FILE command. Note that you should always back up all files at the same time.

4. Restart the Oracle Database using SQL*Plus.

Online Backup

You can perform an online backup of the database or individual tablespaces by using either:

• the BS2000 ARCHIVE utility together with the Oracle Database INSTALL.C.OPNBACK utility

• the BS2000 PERCON utility

The ARCHIVE method is faster, and is described in this section.

Before you can perform an online (hot) backup of individual tablespaces, you must ensure that the ARCHIVE utility can back up open files.

The following BS2000 command ensures that ARCHIVE can back up all open files:

/START-PROGRAM  $ORAC1020.INSTALL.C.OPNBACK
*<filename>

The INSTALL.C.OPNBACK utility calls the BS2000 macro CATAL, which sets the OPNBACK file attribute to YES. For the CATAL macro to work the database must be shut down or the tablespace in question must be offline. You enter this command once for each file. For example, before adding it to a tablespace, not on the occasion of each backup.

You must never back up database files online without first setting the tablespace to backup mode. If you do not follow this step, then the resulting backup files will be inconsistent. To perform an online backup of individual tablespaces or data files, use the following procedure:

1. Enter the following command:

   SQL> ALTER TABLESPACE name BEGIN BACKUP;
   

2. Backup the file(s) of the tablespace using the BS2000 utility ARCHIVE (Make sure that the OLS parameter of ARCHIVE is set to YES).

3. Enter the following command:

   SQL> ALTER TABLESPACE name END BACKUP;
   

Restoring from Backups

An Oracle Database can be restored offline from backups, using the following steps:

1. Copy all the database files and the log files from the backup. You may use the BS2000 ARCHIVE utility or the BS2000 /COPY-FILE command. Files must be restored with their original name.

   While the Oracle database is running, the names of all files which it comprises can be determined by querying the table V$DATAFILE. Enter the following command when the SQL prompt is displayed:

   SELECT * FROM V$DATAFILE;
   

   The following is displayed:

   File        #FILENAME
   ------  -------------------------
   1           ?.DBS.DATABASE1.DBF
   2           ?.DBS.DATABASE2.DBF
    
   2 ROWS SELECTED. 
   

   You can determine the name of the log files in a similar way:

   SQL> SELECT * FROM V$LOGFILE;
   

   The following result is displayed:

   File #       FILENAME
   ------  -------------------------
   1       ?.DBS.LOG1.DBF
   2       ?.DBS.LOG2.DBF
    
   2 ROWS SELECTED. 
   

2. Under the DBA user ID, ensure that the ORASID environment variable identifies the Oracle database, which is to be restored.

3. Use the SQL*Plus STARTUP command to start up the Oracle database.