Manual Recovery of Data Guard Standby Database Oracle Database Tips by Donald BurlesonDecember 9, 2015

Manual Recovery of Data Guard Standby Databases

To start manual recovery of a standby database, mount the database, and start recovery. During the recovery process, the archive logs will be read from the default location specified by the log_archive_dest_n initialization parameter. However, the location of the archived logs can be specified in the RECOVER …DATABASE statement to override the location designated by the log_archive_dest_n parameter.

The following statements start the manual recovery process. It assumes that the oracle_sid is set correctly and the initialization file is in the $ORACLE_HOME/dbs directory. Also, the archived logs are copied from the primary database onto the log_archive_dest_1 location on the standby site:

•  Startup the database:

 STARTUP NOMOUNT;

•  Mount as standby database:

ALTER DATABASE MOUNT STANDBY DATABASE;

•  Start recovery process:

RECOVER STANDBY DATABASE;

Data Guard

Oracle Data GuardChapter 4 - Oracle instance Administration

Manual Recovery of Standby Databases

If the archive logs are not located in the directory specified by the log_archive_dest_1 parameter, the following statement can be used to start recovery reading the log files from other locations:

RECOVER FROM 'archive_log_location' STANDBY DATABASE;

Figure 4.1 - Manual Data Guard Recovery Process

Shutting Down the Standby Database

Before shutting down the standby database, exclude this standby site from the archival operation on the primary database. As long as the Oracle instance is down, the log transfer service will not attempt to write any new archived log files to this standby destination. This parameter can be updated dynamically using the ALTER SYSTEM statement followed by switching a log file on the primary site.

If the database is open in read-only mode, find the active sessions in the database and close the active sessions before issuing the shutdown statement. The following steps show the shut down procedure of the standby database:

• Defer the log transfer service, assuming that this standby site is designated as second destination on the primary database:

ALTER SYSTEM SET
LOG_ARCIVE_DEST_STATE_2=DEFER;

•  Switch a log file on the primary database:

ALTER SYSTEM SWITCH LOGFILE;

• Check the managed recovery process on the standby site:

Select
   Process,
   State
From
   V$MANAGED_STANDBY;

• Cancel the recovery process on the standby site:

ALTER DATABASE RECOVER MANAGED
Oracle instance CANCEL;

• Shutdown the database:

SHUTDOWN IMMEDIATE