Oracle Data Guard consists of the following components. Physical Standby Implementation. Oracle Database 10g: RAC Deployment Workshop Dauer: 4 Tage. Data Guard und Unix/Linux Systemadministration.Learn To. How To Apply A Rolling OPatch Welcome To ABCdba.com ยป. If the the variable online. Patch ID 123456 is registered in Oracle Home inventory with proper. Introduction to Oracle Data Guard. Oracle Data Guard ensures high availability, data protection, and disaster recovery for enterprise data. Data Guard provides a comprehensive set of services that create, maintain, manage, and monitor one or more standby databases to enable production Oracle databases to survive disasters and data corruptions. Data Guard maintains these standby databases as transactionally consistent copies of the production database. Then, if the production database becomes unavailable because of a planned or an unplanned outage, Data Guard can switch any standby database to the production role, minimizing the downtime associated with the outage. Data Guard can be used with traditional backup, restoration, and cluster techniques to provide a high level of data protection and data availability. With Data Guard, administrators can optionally improve production database performance by offloading resource- intensive backup and reporting operations to standby systems. This chapter includes the following topics that describe the highlights of Oracle Data Guard: 1. Data Guard Configurations. A Data Guard configuration consists of one production database and one or more standby databases. The databases in a Data Guard configuration are connected by Oracle Net and may be dispersed geographically. There are no restrictions on where the databases are located, provided they can communicate with each other. To apply this patch set, Oracle OLAP users should ensure that the base release is the Enterprise. Using Data Guard SQL. Database Support Blog. Rolling Upgrade using Active Data Guard. Effective Client Failover in an Oracle Data Guard Environment. Rolling Patch Oracle Data Guard MaximumFor example, you can have a standby database on the same system as the production database, along with two standby databases on other systems at remote locations. You can manage primary and standby databases using the SQL command- line interfaces or the Data Guard broker interfaces, including a command- line interface (DGMGRL) and a graphical user interface that is integrated in Oracle Enterprise Manager. Primary Database. Maximum Availability Architecture (MAA) Best. Online Patching Oracle Clusterware and RAC Rolling Upgrade Data Guard SQL Apply Rolling Upgrade SQL Apply Extended Data. Dave, did you get that patch from Oracle that we. 26 Patching Primary and Standby Databases Configured with Oracle Data Guard. Overview of Patching Primary and Standby Databases. Patch Oracle RAC Rolling. A Data Guard configuration contains one production database, also referred to as the primary database, that functions in the primary role. This is the database that is accessed by most of your applications. The primary database can be either a single- instance Oracle database or an Oracle Real Application Clusters database. Standby Databases. A standby database is a transactionally consistent copy of the primary database. Using a backup copy of the primary database, you can create up to nine standby databases and incorporate them in a Data Guard configuration. Once created, Data Guard automatically maintains each standby database by transmitting redo data from the primary database and then applying the redo to the standby database. Similar to a primary database, a standby database can be either a single- instance Oracle database or an Oracle Real Application Clusters database. A standby database can be either a physical standby database or a logical standby database: Physical standby database. Provides a physically identical copy of the primary database, with on disk database structures that are identical to the primary database on a block- for- block basis. The database schema, including indexes, are the same. A physical standby database is kept synchronized with the primary database, though Redo Apply, which recovers the redo data received from the primary database and applies the redo to the physical standby database. A physical standby database can be used for business purposes other than disaster recovery on a limited basis. Logical standby database. Contains the same logical information as the production database, although the physical organization and structure of the data can be different. The logical standby database is kept synchronized with the primary database though SQL Apply, which transforms the data in the redo received from the primary database into SQL statements and then executing the SQL statements on the standby database. A logical standby database can be used for other business purposes in addition to disaster recovery requirements. This allows users to access a logical standby database for queries and reporting purposes at any time. Also, using a logical standby database, you can upgrade Oracle Database software and patch sets with almost no downtime. Thus, a logical standby database can be used concurrently for data protection, reporting, and database upgrades. Configuration Example. Figure 1- 1 shows a typical Data Guard configuration that contains a primary database that transmits redo data to a standby database. The standby database is remotely located from the primary database for disaster recovery and backup operations. You can configure the standby database at the same location as the primary database. However, for disaster recovery purposes, Oracle recommends you configure standby databases at remote locations. Figure 1- 1 shows a typical Data Guard configuration in which redo is being applied out of standby redo log files to a standby database. Data Guard Services. The following sections explain how Data Guard manages the transmission of redo data, the application of redo data, and changes to the database roles: Redo Transport Services. Control the automated transfer of redo data from the production database to one or more archival destinations. Log Apply Services. Apply redo data on the standby database to maintain transactional synchronization with the primary database. Redo data can be applied either from archived redo log files, or, if real- time apply is enabled, directly from the standby redo log files as they are being filled, without requiring the redo data to be archived first at the standby database. Role Transitions. Change the role of a database from a standby database to a primary database, or from a primary database to a standby database using either a switchover or a failover operation. Redo Transport Services. Redo transport services control the automated transfer of redo data from the production database to one or more archival destinations. Redo transport services perform the following tasks: Transmit redo data from the primary system to the standby systems in the configuration. Manage the process of resolving any gaps in the archived redo log files due to a network failure. Enforce the database protection modes (described in Section 1. Automatically detect missing or corrupted archived redo log files on a standby system and automatically retrieve replacement archived redo log files from the primary database or another standby database. Log Apply Services. The redo data transmitted from the primary database is written on the standby system into standby redo log files, if configured, and then archived into archived redo log files. Log apply services automatically apply the redo data on the standby database to maintain consistency with the primary database. It also allows read- only access to the data. The main difference between physical and logical standby databases is the manner in which log apply services apply the archived redo data: For physical standby databases, Data Guard uses Redo Apply technology, which applies redo data on the standby database using standard recovery techniques of an Oracle database, as shown in Figure 1- 2. For logical standby databases, Data Guard uses SQL Apply technology, which first transforms the received redo data into SQL statements and then executes the generated SQL statements on the logical standby database, as shown in Figure 1- 3. Role Transitions. An Oracle database operates in one of two roles: primary or standby. Using Data Guard, you can change the role of a database using either a switchover or a failover operation. A switchover is a role reversal between the primary database and one of its standby databases. A switchover ensures no data loss. This is typically done for planned maintenance of the primary system. During a switchover, the primary database transitions to a standby role, and the standby database transitions to the primary role. The transition occurs without having to re- create either database. A failover is when the primary database is unavailable. Failover is performed only in the event of a catastrophic failure of the primary database, and the failover results in a transition of a standby database to the primary role. The database administrator can configure Data Guard to ensure no data loss. The role transitions described in this documentation are invoked manually using SQL statements. You can also use the Oracle Data Guard broker to simplify role transitions and automate failovers using Oracle Enterprise Manager or the DGMGRL command- line interface, as described in Section 1. Data Guard Broker. The Data Guard broker is a distributed management framework that automates the creation, maintenance, and monitoring of Data Guard configurations. You can use either the Oracle Enterprise Manager graphical user interface (GUI) or the Data Guard command- line interface (DGMGRL) to: Create and enable Data Guard configurations, including setting up redo transport services and log apply services. Manage an entire Data Guard configuration from any system in the configuration. Manage and monitor Data Guard configurations that contain Real Application Clusters primary or standby databases. Simplify switchovers and failovers by allowing you to invoke them using either a single key click in Oracle Enterprise Manager or a single command in the DGMGRL command- line interface. Enable fast- start failover to fail over automatically when the primary database becomes unavailable. When fast- start failover is enabled, the Data Guard broker determines if a failover is necessary and initiates the failover to the specified target standby database automatically, with no need for DBA intervention and with no loss of data. In addition, Oracle Enterprise Manager automates and simplifies: Creating a physical or logical standby database from a backup copy of the primary database. Adding new or existing standby databases to an existing Data Guard configuration.
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