High Availability « Oracle DBA – Tips and Techniques

Oracle 11g Cross platform Active Standby - Windows Primary database and Linux Active Standby

This note describes the procedure of configuring a cross platform using the 11g RMAN Active Duplicate as well as an Active Standby Database setup over a Windows and Linux platform.

The Metalink note Data Guard Support for Heterogeneous Primary and Physical Standbys in Same Data Guard Configuration [ID 413484.1] describes the supported cross platform combinations between a primary and standby database.

In Oracle 10g, we could have a 32 bit and 64 bit Primary/Standby combination on some supported platforms and in 11g this has been extended to cover heterogenous platforms for the Primary and Standby database.

The environment used is as follows:

Primary

Windows 7 64 bit
11g Release 2
DB_UNIQUE_NAME=orcl

Active Standby

Oracle Enterprise Linux 5.7 64 bit
11g Release 2
DB_UNIUE_NAME=orcl_dr

Read the rest of the note Oracle 11g Cross platform Active Standby – Windows Primary database and Linux Active Standby

Creating a 11g Data Guard Physical Standby Database using Enterprise Manager Grid Control 10.2.0.5

In one of my earlier posts, I had discussed the process of setting up a 11g Standby Database using the DUPLICATE FROM ACTIVE method where we do not use any RMAN backup to create the standby database, but copy the datafiles from an active running database over the network.

Let us now have a look at some of the screenshots of creating a 11g Data Guard physical standby database using Oracle Enterprise Manager Grid Control version 10.2.0.5.

Download ….

11g Active Standby Database Automatic Block Corruption Repair

In addition to the real time query capability of the 11g Active Data Guard feature, we can also add to our high availability capability by using the Automatic Block Media Repair feature whereby data block corruptions on the Primary database can be repaired by obtaining those blocks from the standby site – all performed by a background process (ABMR) transparent to the application.

The same functionality can be used to repair block corruptions on the Active Standby site by applying blocks which are conversely now received from the Primary site.

Let us see a test case of the same.

We create a test table and assign it to the USERS tablespace.

SQL> create table myobjects
2 tablespace users
3 as select * from all_objects;

Table created.

Using DBMS_ROWID, we determine the blocks which this table occupies (if you like, just restrict the query to the first 5 blocks in case the

Continue reading 11g Active Standby Database Automatic Block Corruption Repair

11g Active Data Guard - enabling Real-Time Query

Active Data Guard is a good new feature in 11g (although requires a license) which enables us to query the Standby database while redo logs are being applied to it. In earlier releases, we had to stop the log apply, open the database in read only mode and then start the log apply again when the database was taken out of the read only mode.

With Oracle 11g Active Data Guard, we can make use of our standby site to offload reporting and query type applications while at the same time not compromising on the high availability aspect.

How do we enable Active Data Guard?

If we are not using the Data Guard Broker, we need to open the standby database, set it in read only mode and then start the managed recovery as shown below.

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

SQL> startup
ORACLE instance started.

Total System Global Area 1069252608 bytes
Fixed

Continue reading 11g Active Data Guard – enabling Real-Time Query

EM Grid Control and High Availability

A question often asked is can we use Oracle Data Guard as a high availibility option for the EM Grid Control Repository database. The repository database contains information on all the targets, the jobs configured, alerts and notification history etc. It has a lot of very valuable information and can be deemed as a fairly critical production database especially if there are hundreds of targets and hundreds of jobs defined in EM Grid Control. Also, how do we protect the Application Server part of the Grid Control environment? What do we do if lose the host where the management server resides?

This note will provide an overview of setting up a DR environment for the EM Grid Control Repository database. It will show how using Oracle Data Guard, a database failover is done to the standby site as well as how to set up an additional OMS (Oracle Management Service)

Continue reading EM Grid Control and High Availability

11g Release 2 Rolling Upgrade using Transient Logical Standby database

This note illustrates how we can perform a rolling upgrade from Oracle 11g Release 1 to Oracle 11g Release 2 using a Transient Logical Standby database. This approach will miminise the downtime required for an upgrade which can potentially run into several hours down to just the time required to perform a switchover which could be a few minutes in most cases.

A rolling upgrade using a Transient Logical Standby database at a very high level will involve three main stages or steps:

1) Temporarily convert a physical standby database to a logical standby database using the new KEEP IDENTITY clause
2) Perform a database upgrade of the logical standby database
3) Return the logical standby database back to its identity or original status as a physical standby database once the upgrade is complete

The assumption here is that ….

1)We already have configured a Physical Standby Database using Data Guard best practices and both Primary

Continue reading 11g Release 2 Rolling Upgrade using Transient Logical Standby database

11g Data Guard Broker DGMGRL Configuration quick steps

This note describes the commands used to create a Data Guard broker configuration using the command line dgmgrl interface. This can also be done via the Enterprise Manager Grid Control GUI as well and the assumption is that there is a Physical Standby database in place and redo transport and redo apply have already been configured and that both the Primary and Standby database are in sync.

Primary Database: genoa1_js

Standby Database: genoa1_fc

On both Primary as well as Standby database start the Data Guard Broker process

SQL> ALTER SYSTEM SET DG_BROKER_START=TRUE SCOPE=BOTH;

System altered.

Edit the listener.ora on both nodes to add a static entry for DGMGRL

This is to prevent the ORA-12154 error which can be observed on startup of the standby database after performing a switchover.

Ensure that the GLOBAL_DBNAME is set to db_unique_name_DGMGRL.db_domain

SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(GLOBAL_DBNAME = genoa1_js_dgmgrl)

Continue reading 11g Data Guard Broker DGMGRL Configuration quick steps

Create Standby Database using 11g DUPLICATE FROM ACTIVE DATABASE

Purpose

This note explains the procedure of creating a Physical Standby database using 11g RMAN DUPLICATE FROM ACTIVE DATABASE feature which is now available in 11g Release 1 onwards. This enables us to create a physical standby database without having to take a backup of the primary database as a prerequisite step.

Environment

Primary Database DB_UNIQUE_NAME: genoa1_js
Standby Database DB_UNIQUE_NAME: genoa1_fc

ORACLE_SID: genoa1

Primary hostname: oatu037
Standby hostname: drou037

Oracle software version: Oracle Database 11g Enterprise Edition Release 11.1.0.7.0 – 64bit

Enable Force Logging on the Primary database

SQL> alter database force logging;

Database altered.

Download the note ….

11g Standby database creation without any RMAN backups

Quick steps to set up a 11g Standby database with Active Data Guard using the Active Duplication feature available in 11g where we can create a standby database without having to take a backup on the primary database. Datafiles are copied over the network.

Primary machine – OATU036
Standby machine – DROU036

Database Name – SID1O

TNS alias for Primary – sid1o_fc
TNS alias for standby – sid1o_js

Enable force logging on the Primary database

SQL> alter database force logging;

Database altered.

Create the Standby log files on the Primary database

Copy the password file from the $ORACLE_HOME/dbs directory on primary server to $ORACLE_HOME/dbs on the standby server

Update listener.ora on Standby machine

(SID_DESC=
(GLOBAL_DBNAME=sid1o_js)
(ORACLE_HOME=/u01/oracle/product/11.1.0/db_1)
(SID_NAME=sid1o)
)

Stop and Restart the listener on the standby site

Update tnsnames.ora on Standby as well as Primary site with the alias ‘sid1o_js’ and

Continue reading 11g Standby database creation without any RMAN backups

Oracle Restart – new in 11g R2

Similar to the clusterware processes in a RAC environment, in 11g R2 even for a standalone instance, functionality is now available to automatically restart components like the database, listener, ASM diskgroup, service etc in the event of their failure.

This feature is called Oracle Restart and it runs out of the Grid Infrastructure home which is separate from the database home.

Oracle Restart is managed by CRSCTL utility and it uses Oracle High Availability Services to start and stop the components managed by Oracle Restart.

Using Oracle Restart, we can stop or start all the components running out of a single Oracle Home with a single srvctl command as well as Oracle Restart will automatically start all components on machine reboot in the proper order taking into account dependencies like ASM instance and the managed database instances. So no more do we have to use the dbstart and dbstop scripts to manage this.

Oracle

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