7 Backing Up and Recovering a Database

This chapter supplements the generic Oracle Database documentation set with information about backup and recovery. It includes the following topics:

Refer to the following Oracle manuals for detailed information about database backup and recovery:

You can choose among many methods and Oracle tools for backup and recovery. You may use the Import and Export Utilities for logical backup and recovery. For physical backup and recovery you may use Recovery Manager (RMAN) or operating system utilities.

This chapter describes some BS2000 specific issues if you apply user-managed backup and recovery with SQL*Plus and BS2000 utilities.

Backing Up an Oracle Database

You can use one of the following methods to back up an Oracle 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:

While the database is running, collect the names of all the files, which make up Oracle Database. You can determine the names of the log and database files by entering the following commands:
```
/START-EXECUTABLE (*LINK(ORALOAD),SQLPLUS)
* /NOLOG
SQL> CONNECT / AS SYSDBA
SQL> SELECT * FROM V$DATAFILE;
SQL> SELECT * FROM V$LOGFILE;
```
To ensure that all Oracle database files are synchronized at the time of the backup, shut down Oracle database using SQL*Plus.
Back up all the database files and log files using the BS2000 ARCHIVE utility or the BS2000 /COPY-FILE command. You should always back up all the files at the same time.
Restart Oracle Database using SQL*Plus.

Performing Online Backup

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

The BS2000 ARCHIVE utility together with 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-EXECUTABLE $ORACINST.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 are inconsistent. To perform an online backup of individual tablespaces or data files, use the following procedure:

Enter the following command:

SQL> ALTER TABLESPACE name BEGIN BACKUP;

Back up the files of the tablespace using the BS2000 ARCHIVE utility. Ensure that the OLS parameter of ARCHIVE is set to YES.
Enter the following command:
```
SQL> ALTER TABLESPACE name END BACKUP;
```

Note:

The preceding SQL*Plus commands operate on tablespaces, while the ARCHIVE utility operates on data files.

Restoring an Oracle Database

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

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.
To determine the name of all data files, query the V$DATAFILE table while the Oracle database is running. Enter the following command when the SQL prompt is displayed:
```
SQL> SELECT FILE#,NAME FROM V$DATAFILE;
```
The following is an example of the result that is displayed:
```
FILE#  NAME
------  -------------------------
1     :pvs:$dbauserid.sid.DBS.DATABASE1.DBF
2     :pvs:$dbauserid.sid.DBS.DATABASE2.DBF
 
2 ROWS SELECTED. 
```
You can determine the name of the log files in a similar way:
```
SQL> SELECT GROUP#,MEMBER FROM V$LOGFILE;
```
The following is an example of the result that is displayed:
```
GROUP# MEMBER
------  -------------------------
1         :pvs:$dbauserid.sid.DBS.LOG1.DBF
2         :pvs:$dbauserid.sid.DBS.LOG2.DBF
 
2 ROWS SELECTED. 
```
Under the DBA user ID, ensure that the ORASID environment variable identifies the Oracle Database, which is to be restored.
Use the SQL*Plus STARTUP command to start the Oracle database.

About Using the Recovery Manager

In addition to the BS2000 utilities, you can also use Oracle Recovery Manager (RMAN) to back up and restore a database.