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Data Guard Operational Prerequisites


Learn Oracle - User Interfaces for Administering Data Guard Configurations

You can use the following interfaces to configure, implement, and manage a Data Guard configuration:
  • Oracle Enterprise Manager

    Enterprise Manager provides a GUI interface for the Data Guard broker that automates many of the tasks involved in creating, configuring, and monitoring a Data Guard environment.

  • SQL*Plus Command-line interface

    Several SQL*Plus statements use the STANDBY keyword to specify operations on a standby database. Other SQL statements do not include standby-specific syntax, but they are useful for performing operations on a standby database.

  • Initialization parameters

    Several initialization parameters are used to define the Data Guard environment. We will see them in the coming chapters.

  • Data Guard broker command-line interface (DGMGRL)

    The DGMGRL command-line interface is an alternative to using Oracle Enterprise Manager. The DGMGRL command-line interface is useful if oracle DBA want to use the broker to manage a Data Guard configuration from batch programs or scripts.

Learn Oracle - Data Guard Operational Prerequisites

The following sections describe operational requirements for using Data Guard:
Hardware and Operating System Requirements
Oracle Software Requirements

Learn Oracle - Hardware and Operating System Requirements

The following list describes hardware and operating system requirements for using Data Guard:

  • All members of a Data Guard configuration must run an Oracle image that is built for the same platform. For example, this means a Data Guard configuration with a primary database on a 32-bit Linux on Intel system can have a standby database that is configured on a 32-bit Linux on Intel system. However, a primary database on a 64-bit HP-UX system can also be configured with a standby database on a 32-bit HP-UX system, as long as both servers are running 32-bit images.

  • The hardware (for example, the number of CPUs, memory size, storage configuration) can be different between the primary and standby systems. If the standby system is smaller than the primary system, oracle DBA may have to restrict the work that can be done on the standby system after a switchover or failover. The standby system must have enough resources available to receive and apply all redo data from the primary database. The logical standby database requires additional resources to translate the redo data into SQL statements and then execute the SQL on the logical standby database.

  • The operating system running on the primary and standby locations must be the same, but the operating system release does not need to be the same. In addition, the standby database can use a different directory structure from the primary database.

Learn Oracle - Oracle Software Requirements

The following list describes Oracle software requirements for using Data Guard:

  • Oracle Data Guard is available only as a feature of Oracle Database Enterprise Edition. It is not available with Oracle Database Standard Edition. This means the same release of Oracle Database Enterprise Edition must be installed on the primary database and all standby databases in a Data Guard configuration.

  • Using Data Guard SQL Apply, oracle DBA will be able to perform a rolling upgrade of the Oracle database software from patch set release n (minimally, this must be release to the next database 10.1.0.(n+1) patch set release. During a rolling upgrade, oracle DBA can run different releases of the Oracle database on the primary and logical standby databases while you upgrade them, one at a time.

  • The COMPATIBLE initialization parameter must be set to the same value on all databases in a Data Guard configuration.

  • The primary database must run in ARCHIVELOG mode. The primary database can be a single instance database or a multi-instance Real Application Clusters database. The standby databases can be single instance databases or multi-instance Real Application Clusters (RAC) databases, and these standby databases can be a mix of both physical and logical types.

  • Each primary database and standby database must have its own control file.

  • If a standby database is located on the same system as the primary database, the archival directories for the standby database must use a different directory structure than the primary database. Otherwise, the standby database may overwrite the primary database files.

  • To protect against unlogged direct writes in the primary database that cannot be propagated to the standby database, turn on FORCE LOGGING at the primary database before performing data file backups for standby creation. Keep the database in FORCE LOGGING mode as long as the standby database is required.

  • The user accounts you use to manage the primary and standby database instances must have SYSDBA system privileges.

  • Oracle recommends that when oracle DBA set up Oracle Automatic Storage Management (ASM) and Oracle Managed Files (OMF) in a Data Guard configuration, set it up symmetrically on the primary and standby database. That is, if any database in the Data Guard configuration uses ASM, OMF, or both, then every database in the configuration should use ASM, OMF, or both, respectively.

Related Topics:

Learn Oracle - Oracle Data Guard
Learn Oracle - Standby Database Types


We learned Standby database types today. Next we will move to User Interfaces for Administering Data Guard Configurations.

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