Creating a Data Guard Configuration

1) Ensure the Primary database is in ARCHIVELOG mode:

SQL> archive log list
Database log mode No Archive Mode
Automatic archival Disabled
Archive destination /export/home/oracle/temp/oracle/arch
Oldest online log sequence 7
Current log sequence 9
SQL> alter database close;

Database altered.

SQL> alter database archivelog;

Database altered.

SQL> shutdown immediate
ORA-01109: database not open


Database dismounted.
ORACLE instance shut down.

Modify the Primary database init.ora so that log_archive_start=true and restart
the instance. Verify that database is in archive log mode and that automatic
archiving is enabled.

SQL> archive log list
Database log mode Archive Mode
Automatic archival Enabled
Archive destination /export/home/oracle/temp/oracle/arch
Oldest online log sequence 7
Next log sequence to archive 9
Current log sequence 9

2) Create a backup of the Primary database:

You can use an existing backup of the Primary database as long as you have the
archive logs that have been generated since that backup. You may also take a
hot backup as long as you have all archive logs through the end of the backup
of the last tablespace. To create a cold backup do the following:

SQL>
SQL> select name from v$datafile;

NAME
----------------------------------------------------------------------
/export/home/oracle/temp/oracle/data/sys.dbf

SQL>
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> exit

Create a backup of all datafiles and online redo logs using an OS command or
utility. A backup of the online redo logs is necessary to facilitate switchover.

Once complete startup the instance:

SQL> startup
ORACLE instance started.

Total System Global Area 80512156 bytes
Fixed Size 279708 bytes
Variable Size 71303168 bytes
Database Buffers 8388608 bytes
Redo Buffers 540672 bytes
Database mounted.
Database opened.

3) Connect to the primary database and create the standby control file:

SQL> alter database create standby controlfile as
'/export/home/oracle/temp/oracle/data/backup/standby.ctl';

Database altered.

4) Copy files to the Standby host:

Copy the backup datafiles, standby controlfile, all available archived redo logs,
and online redo logs from the primary site to the standby site. Copying of the
online redo logs is necessary to facilitate switchover.

If the standby is on a separate site with the same directory structure as the
primary database then you can use the same path names for the standby files as
the primary files. In this way, you do not have to rename the primary datafiles
in the standby control file. If the standby is on the same site as the primary
database, or the standby database is on a separate site with a different
directory structure the you must rename the primary datafiles in the standby
control file after copying them to the standby site. This can be done using
the db_file_name_convert and log_file_name_convert parameters or by manually
using the alert database statements.

5) Set the initialization parameters for the primary database:

It is suggested that you maintain two init.ora’s on both the primary and the
standby. This allows you to facilitate role reversal during switchover
operations more easily.

Primary init.ora on Primary host:

log_archive_dest_1='LOCATION=/export/home/oracle/temp/oracle/arch'
log_archive_dest_2='SERVICE=DGD01_hasunclu2 reopen=60'
log_archive_dest_state_1=enable
log_archive_dest_state_2=enable
log_archive_format=%t_%s.dbf
log_archive_start=true
remote_archive_enable=true

Create the standby initialization parameter file and set the initialization
parameters for the standby database. Depending on your configuration, you may
need to set filename conversion parameters.

Standby init.ora on Primary host:

log_archive_dest_1='LOCATION=/export/home/oracle/temp/oracle/arch'
log_archive_dest_state_1=enable
log_archive_format=%t_%s.dbf
log_archive_start=true
standby_archive_dest=/export/home/oracle/temp/oracle/arch
standby_file_management=auto
fal_server=DGD01_hasunclu2
fal_client=DGD01_hasunclu1
remote_arhive_enable=true

NOTE: In the above example db_file_name_convert and log_file_name_convert are
not needed as the directory structure on the two hosts are the same. If the
directory structure is not the same then setting of these parameters is
recommended. Please reference notes 47325.1 and 47343.1 for further
information.

Copy the two init.ora’s from the Primary host to the Standby host. You must
modify the Primary init.ora on the Standby host to have log_archive_dest_2 use
the alias that points to the Primary host (ie DGD01_hasunclu1). You must
modify the Standby init.ora on the standby host to have fal_server and
fal_client use the aliases when standby is running on the Primary host
(ie fal_server=DGD01_hasunclu1 and fal_client=DGD01_hasunclu2).

6) Configure networking components:

On the Primary host create a net service name that the Primary database can
use to connect to the Standby database. On the Primary host create a net
service name that Standby, when running on the Primary host, can use to
connect to the Primary, when it is running on the Standby host. Example from
Primary’s host tnsnames.ora:

DGD01_hasunclu1 =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = hasunclu1)(PORT = 1521))
)
(CONNECT_DATA =
(SID = DGD01)
(SERVER = DEDICATED)
)
)
DGD01_hasunclu2 =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = hasunclu2)(PORT = 1521))
)
(CONNECT_DATA =
(SID = DGD01)
(SERVER = DEDICATED)
)
)

The above two net service names must exist in the Standby hosts tnsnames.ora
also.

You must also configure a listener on the standby database. If you plan to
manage this standby database using the Data Guard broker, you must configure
the listener to use the TCP/IP protocol and statically register the standby
database service using its SID.


7) Start the standby instance and mount the standby database.

oracle@hasunclu2:/export/home/oracle/temp/oracle> sqlplus "/ as sysdba"

SQL*Plus: Release 9.0.1.0.0 - Production on Thu Mar 14 18:00:57 2002

(c) Copyright 2001 Oracle Corporation. All rights reserved.

Connected to an idle instance.

SQL> startup nomount pfile=?/dbs/initDGD.ora
ORACLE instance started.

Total System Global Area 80512156 bytes
Fixed Size 279708 bytes
Variable Size 71303168 bytes
Database Buffers 8388608 bytes
Redo Buffers 540672 bytes
SQL> alter database mount standby database;

Database altered.

SQL>

8) Create standby redo log files, if necessary:

Standby redo logs are necessary for the higher protection levels such as
Guaranteed, Instant, and Rapid. In these protection modes LGWR from the
Primary host writes transactions directly to the standby redo logs.
This enables no data loss solutions and reduces the amount of data loss
in the event of failure. Standby redo logs are not necessary if you are using
the delayed protection mode.

If you configure standby redo on the standby then you should also configure
standby redo logs on the primary database. Even though the standby redo logs
are not used when the database is running in the primary role, configuring
the standby redo logs on the primary database is recommended in preparation
for an eventual switchover operation.

Standby redo logs must be archived before the data can be applied to the
standby database. The standby archival operation occurs automatically, even if
the standby database is not in ARCHIVELOG mode. However, the archiver process
must be started on the standby database. Note that the use of the archiver
process (ARCn) is a requirement for selection of a standby redo log.

You must have the same number of standby redo logs on the standby as you have
online redo logs on production. They must also be exactly the same size.

The following syntax is used to create standby redo logs:

SQL> alter database add standby logfile
2 '/export/home/oracle/temp/oracle/data/srl_1.dbf' size 20m;

Database altered.
SQL> alter database add standby logfile
2 '/export/home/oracle/temp/oracle/data/srl_2.dbf' size 20m;

Database altered.

SQL> alter database add standby logfile
2 '/export/home/oracle/temp/oracle/data/srl_3.dbf' size 20m;

Database altered.

SQL>

9) Manually change the names of the primary datafiles and redo logs in the
standby control file for all files not automatically renamed using
DB_FILE_NAME_CONVERT and LOG_FILE_NAME_CONVERT as noted in step 5. Datafile
names can be changed on the standby at a mounted state with the following
syntax:

SQL> alter database rename file
2 '/export/home/oracle/temp/oracle/data/sys.dbf'
3 to
4 '/export/home/oracle/temp/oracle/data2/sys.dbf';

10) Stop and restart the listeners:

On the primary database, and start the listener on the standby database so that
changes made to the listener.ora can be implemented.

11) Activate parameter changes:

Manually enable initialization parameter changes on the primary database
so that it can initiate archiving to the standby site.

At runtime, the LOG_ARCHIVE_DEST_n initialization parameter can be changed
using ALTER SYSTEM and ALTER SESSION statements. Activate the changes made to
these parameters by either bouncing the instance or activating via alter system.
For example:

SQL> alter system set log_archive_dest_2='SERVICE=DGD01_hasunclu2 reopen=60';

System altered.

12) Verify that automatic archiving is occurring:

On the Primary database switch a log and verfy that it has been shipped
properly using the v$archive_dest view.

SQL> alter system switch logfile;

System altered.

SQL> select status, error from v$archive_dest where dest_id=2;

STATUS ERROR
--------- -------------------------------------------------------
VALID

SQL>

13) Optionally place Standby database in managed recovery:

SQL> recover managed standby database disconnect;
Media recovery complete.
SQL> exit