MAA - Creating a Single Instance Physical Standby for a RAC Primary

Subject: MAA - Creating a Single Instance Physical Standby for a RAC Primary
Doc ID: Note:387339.1 Type: WHITE PAPER
Last Revision Date: 14-AUG-2006 Status: PUBLISHED

MAA / Data Guard 10g Setup Guide –

Creating a Single Instance
Physical Standby for a RAC Primary


Oracle Maximum Availability Architecture White Paper

April 2006



Overview
Oracle Maximum Availability Architecture (MAA) [1] is Oracle's best practices blueprint based on proven Oracle high-availability technologies and recommendations. The goal of MAA is to remove the complexity in designing the optimal high-availability architecture.

Published as part of the MAA series of white papers, this paper focuses on creating a single instance physical standby database for a RAC primary database. This document assumes that there is an existing RAC database and you want to implement Data Guard by adding a physical standby database to the configuration. The end configuration for this document is a RAC primary database with a single-instance physical standby database. The steps outlined in this document use SQL*Plus, apply to both Oracle Database 10g Release 1 and Oracle Database 10g Release 2, and they assume using ASM/OMF, and that the software and ASM instance on the standby host have already been installed/created.

The example used in this document has the database unique name of the RAC database as CHICAGO. The instance names of the two RAC instances are CHICAGO1 (on node chicago_host1) and CHICAGO2 (on node chicago_host2). The database unique name of the single-instance physical standby database is BOSTON (on node boston_host1).

This document includes the following tasks:

Task 1: Gather Files and Perform Back Up
Task 2: Configure Oracle Net on the Physical Standby
Task 3: Create the Physical Standby Instance and Database
Task 4: Configure the Primary Database for Data Guard
Task 5: Verify Data Guard Configuration
This document assumes that the following conditions are met:

The primary RAC database is using ASM.
The standby host has an existing Oracle software installation.
The physical standby database storage uses an existing ASM instance.
The primary and standby databases are using a flash recovery area.
Oracle Managed Files (OMF) is used for all storage.


Task 1: Gather Files and Perform Back Up

On the primary node, create a staging directory. For example:
[oracle@chicago_host1 oracle]$ mkdir -p /opt/oracle/stage


Create the same exact path on the standby host:
[oracle@boston_host1 oracle]$ mkdir -p /opt/oracle/stage


On the primary node, connect to the primary database and create a PFILE from the SPFILE in the staging directory. For example:
SQL> CREATE PFILE='/opt/oracle/stage/initCHICAGO.ora' FROM SPFILE;


On the primary node, perform an RMAN backup of the primary database that places the backup pieces into the staging directory. For example:
[oracle@chicago_host1 stage]$ rman target /
RMAN> backup device type disk format '/opt/oracle/stage/%U' database plus archivelog;
RMAN> backup device type disk format '/opt/oracle/stage/%U' current controlfile for standby;


Place a copy of the listener.ora, tnsnames.ora, and sqlnet.ora files into the staging directory. For example:
[oracle@chicago_host1 oracle]$ cp $ORACLE_HOME/network/admin/*.ora /opt/oracle/stage


Copy the contents of the staging directory on the RAC node to the staging directory on the standby host. For example:
[oracle@chicago_host1 oracle]$ scp /opt/oracle/stage/* oracle@boston_host1:/opt/oracle/stage

Task 2: Configure Oracle Net SERVICES on the Standby

Copy the listener.ora, tnsnames.ora, and sqlnet.ora files from the staging directory on the standby host to the $ORACLE_HOME/network/admin directory on the standby host.
Modify the listener.ora file on the standby host to contain the hostname of the standby host.
Modify the tnsnames.ora file on each node, including the primary RAC nodes and standby host, to contain all primary and standby net service names. In this example, each tnsnames.ora file should contain all three of the net service names in the following table:
Example Entries in the tnsnames.ora Files

Primary Net Service Names Standby Net Service Name
CHICAGO1_SERV = (DESCRIPTION = (ADDRESS =
(PROTOCOL = TCP)
(HOST =chicago_host1vip)
(PORT = 1521))
(CONNECT_DATA =
(SERVER =DEDICATED)
(SERVICE_NAME =CHICAGO)
(INSTANCE_NAME =CHICAGO1)
)
)
BOSTON =
(DESCRIPTION =
(ADDRESS =
(PROTOCOL = TCP)
(HOST =boston_host1)
(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = BOSTON)
)
)

CHICAGO2_SERV =
(DESCRIPTION =
(ADDRESS =
(PROTOCOL = TCP)
(HOST = chicago_host2vip)
(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = CHICAGO)
(INSTANCE_NAME = CHICAGO2)
)
)



Task 3: Create the Physical Standby Instance and Database

To enable secure transmission of redo data, make sure the primary and physical standby databases use a password file, and make sure the password for the SYS user is identical on every system. For example:
$ cd $ORACLE_HOME/dbs

$ orapwd file=orapwBOSTON password=oracle


The naming and location of the password file varies on different platforms. See “Creating and Maintaining a Password File” in the Oracle Database Administrator’s Guide for more information.

Copy and rename the primary database PFILE from the staging area on the standby host to the $ORACLE_HOME/dbs directory on the standby host. For example:
[oracle@boston_host1 stage]$ cp initCHICAGO.ora $ORACLE_HOME/dbs/initBOSTON.ora


Modify the standby initialization parameter file copied from the primary node to remove RAC parameters and to include Data Guard parameters as illustrated in the following table:
Initialization Parameter Modifications

arameter
Category
Before After

RAC Parameters *.cluster_database=true
*.db_unique_name=CHICAGO
CHICAGO1.instance_name=CHICAGO1
CHICAGO2.instance_name=CHICAGO2
CHICAGO1.instance_number=1
CHICAGO2.instance_number=2
CHICAGO1.thread=1
CHICAGO2.thread=2
CHICAGO1.undo_tablespace=UNDOTBS1
CHICAGO2.undo_tablespace=UNDOTBS2
*.remote_listener=LISTENERS_CHICAGO
CHICAGO1.LOCAL_LISTENER=LISTENER_CHICAGO_HOST1
CHICAGO2.LOCAL_LISTENER=LISTENER_CHICAGO_HOST2
*.cluster_database=false
*.db_unique_name=BOSTON
*.instance_name=BOSTON
*.thread=1
*.undo_tablespace=UNDOTBS1


Data Guard Parameters
*.log_archive_config='dg_config=
(BOSTON,CHICAGO)'
*.log_archive_dest_2='service=CHICAGO1_SERV
valid_for=(online_logfiles,primary_role)
db_unique_name=CHICAGO'
*.db_file_name_convert='+DATA/CHICAGO/',
'+DATA/BOSTON/','+RECOVERY/CHICAGO',
'+RECOVERY/BOSTON'
*.log_file_name_convert='+DATA/CHICAGO/',
'+DATA/BOSTON/','+RECOVERY/CHICAGO',
'+RECOVERY/BOSTON'
*.standby_file_management=auto
*.fal_server='CHICAGO1_SERV','CHICAGO2_SERV'
*.fal_client='BOSTON'
*.service_names='BOSTON'


Other parameters *.background_dump_dest=
/opt/oracle/admin/CHICAGO/bdump
*.core_dump_dest=
/opt/oracle/admin/CHICAGO/cdump
*.user_dump_dest=
/opt/oracle/admin/CHICAGO/udump
*.audit_file_dest=
/opt/oracle/admin/CHICAGO/adump
*.db_recovery_dest=’+RECOVERY’
*.log_archive_dest_1 =
'LOCATION=+DATA/CHICAGO/'
*.dispatchers=CHICAGOXDB

*.background_dump_dest=
/opt/oracle/admin/BOSTON/bdump
*.core_dump_dest=
/opt/oracle/admin/BOSTON/cdump
*.user_dump_dest=
/opt/oracle/admin/BOSTON/udump
*.audit_file_dest=
/opt/oracle/admin/BOSTON/adump
*.db_recovery_dest=’+RECOVERY’
*.log_archive_dest_1=
'LOCATION=USE_DB_RECOVERY_FILE_DEST'
*.dispatchers=BOSTONXDB





For more information about these initialization parameters, see Chapter 13, “Initialization Parameters” in Oracle Data Guard Concepts and Administration manual.

If you are using an SPFILE instead of an initialization parameter file, then see the “Managing Initialization Parameters Using a Server Parameter File” section in the Oracle Database Administrator’s Guide for instructions on managing an SPFILE.

Connect to the ASM instance on the standby host, and create a directory within the DATA disk group that has the same name as the DB_UNIQUE_NAME of the physical standby database. For example:
SQL> alter diskgroup data add directory '+DATA/BOSTON';


Connect to the physical standby database, with the standby in the IDLE state, and create an SPFILE in the standby DATA disk group:
SQL> CREATE SPFILE='+DATA/BOSTON/spfileBOSTON.ora' FROM PFILE='?/dbs/initBOSTON.ora';


In the $ORACLE_HOME/dbs directory on the standby host, create a PFILE that is named initoracle_sid.ora that contains a pointer to the SPFILE. For example:
[oracle@boston_host1 oracle]$ cd $ORACLE_HOME/dbs
[oracle@boston_host1 dbs]$ echo "SPFILE='+DATA/BOSTON/spfileBOSTON.ora'" > initBOSTON.ora


Create the dump directories on the standby host as referenced in the standby initialization parameter file. For example:
[oracle@boston_host1 oracle]$ mkdir -p $ORACLE_BASE/admin/BOSTON/bdump
[oracle@boston_host1 oracle]$ mkdir -p $ORACLE_BASE/admin/BOSTON/cdump
[oracle@boston_host1 oracle]$ mkdir -p $ORACLE_BASE/admin/BOSTON/udump
[oracle@boston_host1 oracle]$ mkdir -p $ORACLE_BASE/admin/BOSTON/adump


After setting up the appropriate environment variables on the standby host, such as ORACLE_SID, ORACLE_HOME, and PATH, start the physical standby database instance without mounting the control file.
SQL> STARTUP NOMOUNT


From the standby host, duplicate the primary database as a standby into the ASM disk group. For example:
$ rman target sys/oracle@CHICAGO1_SERV auxiliary /
RMAN> duplicate target database for standby;


Connect to the physical standby database, and create the standby redo logs to support the standby role. The standby redo logs must be the same size as the primary database online logs. The recommended number of standby redo logs is:
(maximum # of logfiles +1) * maximum # of threads


This example uses two online log files for each thread. Thus, the number of standby redo logs should be (2 + 1) * 2 = 6. That is, one more standby redo log file for each thread.

SQL> ALTER DATABASE ADD STANDBY LOGFILE THREAD 1
GROUP 5 SIZE 10M,
GROUP 6 SIZE 10M,
GROUP 7 SIZE 10M;

SQL> ALTER DATABASE ADD STANDBY LOGFILE THREAD 2
GROUP 8 SIZE 10M,
GROUP 9 SIZE 10M,
GROUP 10 SIZE 10M;

These statements create two standby log members for each group, and each member is 10MB in size. One member is created in the directory specified by the DB_CREATE_FILE_DEST initialization parameter, and the other member is created in the directory specified by DB_RECOVERY_FILE_DEST initialization parameter. Because this example assumes that there are two redo log groups in two threads, the next group is group five.

You can check the number and group numbers of the redo logs by querying the V$LOG view:

SQL> SELECT * FROM V$LOG;


You can check the results of the previous statements by querying the V$STANDBY_LOG view:

SQL> SELECT * FROM V$STANDBY_LOG;


You can also see the members created by querying the V$LOGFILE view:

SQL> SELECT * FROM V$LOGFILE;


See the “Configure a Standby Redo Log” section in Oracle Data Guard Concepts and Administration manual for more information.

Start managed recovery and real-time apply on the standby database:
SQL> ALTER DATABASE recover managed standby database using current logfile disconnect;

Task 4: Configure The Primary Database For Data Guard
Configure the primary database initialization parameters to support both the primary and standby roles.
*.log_archive_config='dg_config=(BOSTON,CHICAGO)'
*.log_archive_dest_2='service=BOSTON
valid_for=(online_logfiles,primary_role)
db_unique_name=BOSTON'
*.db_file_name_convert='+DATA/BOSTON/',’+DATA/CHICAGO/', ’+RECOVERY/BOSTON’,’+RECOVERY/CHICAGO’
*.log_file_name_convert='+DATA/BOSTON/',’+DATA/CHICAGO/', ’+RECOVERY/BOSTON’,’+RECOVERY/CHICAGO’
*.standby_file_management=auto
*.fal_server='BOSTON'
CHICAGO1.fal_client='CHICAGO1_SERV'
CHICAGO2.fal_client='CHICAGO2_SERV'
*.service_names=CHICAGO

For more information about these initialization parameters, see Chapter 13, “Initialization Parameters” in the Oracle Data Guard Concepts and Administration manual.

If you are using an SPFILE instead of an initialization parameter file, then see the “Managing Initialization Parameters Using a Server Parameter File” section in the Oracle Database Administrator’s Guide for instructions on managing an SPFILE.

Note that all the parameters listed above can be dynamically modified with the exception of the standby role parameters log_file_name_convert and db_file_name_convert. It is recommended to set the parameters with “scope=spfile” so that they can be put into effect upon the next role change.

Create standby redo logs on the primary database to support the standby role. The standby redo logs are the same size as the primary database online logs. The recommended number of standby redo logs is one more than the number of online redo logs for each thread. Because this example has two online redo logs for each thread, three standby redo logs are required for each thread.
SQL> ALTER DATABASE ADD STANDBY LOGFILE THREAD 1
GROUP 5 SIZE 10M,
GROUP 6 SIZE 10M,
GROUP 7 SIZE 10M;


SQL> ALTER DATABASE ADD STANDBY LOGFILE THREAD 2
GROUP 8 SIZE 10M,
GROUP 9 SIZE 10M,
GROUP 10 SIZE 10M;


These statements create two standby log members for each group, and each member is 10MB in size. One member is created in the directory specified by the DB_CREATE_FILE_DEST initialization parameter, and the other member is created in the directory specified by DB_RECOVERY_FILE_DEST initialization parameter. Because this example assumes that there are two redo log groups in two threads, the next group is group five.

You can check the number and group numbers of the redo logs by querying the V$LOG view:

SQL> SELECT * FROM V$LOG;


You can check the results of the previous statements by querying the V$STANDBY_LOG view:

SQL> SELECT * FROM V$STANDBY_LOG;


You can also see the members created by querying the V$LOGFILE view:

SQL> SELECT * FROM V$LOGFILE;


See the “Configure a Standby Redo Log” section in Oracle Data Guard Concepts and Administration manual for more information.


Task 5: Verify Data Guard Configuration

On the physical standby database, query the V$ARCHIVED_LOG view to identify existing files in the archived redo log. For example:
SQL> select sequence#, first_time, next_time
from v$archived_log order by sequence#;


On the primary database, issue the following SQL statement to force a log switch and archive the current online redo log file group:
SQL> alter system archive log current;


On the physical standby database, query the V$ARCHIVED_LOG view to verify that the redo data was received and archived on the standby database:
SQL> select sequence#, first_time, next_time
from v$archived_log order by sequence#;



References

Oracle Maximum Availability Architecture website on OTN
http://www.oracle.com/technology/deploy/availability/htdocs/maa.htm