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    Database Backup:Prepare for the restoration of a standalone Oracle database

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    Database Backup:Prepare for the restoration of a standalone Oracle database

    Last Updated:Dec 20, 2023

    This topic describes the preparations that you must make on the destination server before you restore a standalone Oracle database.

    Overview

    Install a backup gateway

    Database Backup (DBS) uses Database Gateway (DG) to restore databases that have been backed up to on-premises databases or databases that are hosted on third-party clouds. You must install a backup gateway on the destination server. For more information, see Install a backup gateway.

    Note

    DG allows you to connect an on-premises database to a cloud service. You do not need to expose ports to the Internet. DG is a database connection service for remote access to databases deployed on private networks. For more information, see What is Database Gateway?

    If you want to restore a database to the original server that hosts the database, you can select the backup gateway that is used when the database is backed up.

    Check the version of the source Oracle database

    If you use DBS to restore an Oracle database, make sure that the version of Oracle on the destination server is the same as the minor version of the source Oracle database.

    Note

    For example, Oracle 11.2.0.4 is incompatible with Oracle 11.2.0.1. If the source database adopts one of the preceding versions and the destination server adopts the other, errors may occur when you restore data. We recommend that you deploy the same version of Oracle on both the source database and the destination server.

    • You can run the following command to query the Oracle version of the source database:

      su - oracle
export ORACLE_SID=orcl;
sqlplus / as sysdba
select version from v$instance;

      The following output indicates that the Oracle version is 19.0.0.0.0 

      ====================
VERSION
-----------------
19.0.0.0.0
====================

    • If the source database cannot reach the mount state, you can run the following command to query the Oracle version:

      su - oracle
ORACLE_HOME/OPatch/opatch lsinv -oh $ORACLE_HOME |grep ^"Oracle Database"

    Create an SID

    An Oracle SID must be unique on a server. You must create an SID for the destination Oracle database.

    Oracle databases that have the same name cannot run on the same server at the same time. You can run the following commands to stop the source database:

    su - oracle
export ORACLE_SID=orcl;
sqlplus / as sysdba
shutdown abort;      /* You can also run the shutdown immediate; command.*/
exit;

    You can run the following command to check whether the source database is stopped: 

    ps -ef|grep pmon|grep orcl

    If the output of the preceding command is returned, you can run the kill -9 command to stop the database.

    Create a database restoration directory

    Before you create a database restoration directory, you must obtain the size of the storage space that the source database occupies. To ensure that you have enough space for restoration, we recommend that you reserve at least 1.3 times the size of the source database or five to six times the size of the DBS full backup set for the database restoration directory. Data is compressed when DBS performs the backup operation.

    • You can run the following command to query the size of the source database as a user whose name is oracle: 

      su - oracle
export ORACLE_SID=orcl;
sqlplus / as sysdba
select sum(bytes) from ( select bytes from v$datafile union all select bytes from v$tempfile union all select bytes*members bytes from v$log);

      The following output indicates that the size of the database is 4,904,189,952 bytes.

      =======================
SUM(BYTES)
----------
4904189952
=======================

    • You can view the size of the full backup set in the DBS console. Log on to the DBS console. In the left-side navigation pane, click Backup Schedules. On the Backup Schedules page, find the backup schedule of the source database and click the name of the backup schedule. In the left-side navigation pane, choose Backup Tasks > Full Data. On the page that appears, you can view the size of the full backup set. For more information, see View a backup schedule.

    1. Create a directory 

      mkdir -p /Oracle/data_bak

      For example, you can run the preceding command to create a directory named data_bak in the Oracle folder.

      Note

      If the directory already exists, make sure that the directory is empty to prevent the original data in the directory from being overwritten when DBS restores data.

    2. Grant permissions.

      1. You can run the following command to query the user group to which the $ORACLE_HOME/bin/Oracle file belongs: 

        ls -alh $ORACLE_HOME/bin/oracle

        The following output indicates that the $ORACLE_HOME/bin/Oracle file belongs to the oracle:oinstall user group:

        ====================
-rwsr-s--x 1 oracle oinstall 421M Mar 15 03:04 /opt/oracle/product/19c/dbhome_1/bin/oracle
====================

      2. You can run the following command to change the user group of the created directory: 

        chown -R oracle:oinstall /oracle/data_bak

    Obtain the directory of the database client

    ORACLE_HOME specifies the directory in which an Oracle database is installed.

    1. Run the su - oracle command in the CLI to log on to the Oracle database.

    2. Execute the echo ORACLE_HOME statement on the Oracle database to obtain the value of ORACLE_HOME.

      The following output indicates that the value of ORACLE_HOME is /opt/oracle/product/19c/dbhome_1:

      /opt/oracle/product/19c/dbhome_1