NetVault Plug-in for Oracle 12.2 - User Guide

Back up from both Primary and Standby

Offloading resource-intensive backup operations to the Standby Database Server is often one of the drivers for deploying Data Guard. The Oracle version dictates how much of the backup operations can be offloaded to the Standby Database Server:

While Oracle 11.x does not require all backups to be performed on the Standby Database Server, a valid strategy for an Oracle 11.x environment is to mimic the requirements of a 10.2.x environment. In a 10.2.x environment, only datafiles and archived redo log files are offloaded to the Standby Database Server while the Control Files and SPFILE backups are performed from the Primary Database Server.

Another valid strategy for Oracle 10.2.x and 11.x is to perform Control File and SPFILE backups from the Primary Database Server while alternating the backups of the datafiles and archived redo log files between the Primary Database Server and the Standby Database Server. For example, Incremental Level 0 Backups are performed weekly on the Standby Database Server and the Incremental Level 1 backups are performed daily from the Primary Database Server. In addition, daily backups of the Control File and SPFILE are performed from the Primary Database Server.

Oracle’s Maximum Availability Architecture (MAA) best practices recommend that backups be taken at both the primary and the standby databases to reduce MTTR, in case of double outages and to avoid introducing new site practices on switchover and failover.

With this strategy, Plug‑in for Oracle is installed on both the Primary and at least one of the Standby Database Servers that performs backups.

NOTE: For Oracle versions before Oracle 11.x, backups of SPFILE were assumed to be usable at any other standby database. However, in practice, all standby databases cannot use the same SPFILE. Therefore, RMAN does not allow an SPFILE backup taken at one database site to be used at a different database site. This restriction is in place only when the COMPATIBLE initialization parameter is set to 11.0.0. The standby database lets you offload all backup operations to one specific standby database, except the backups of SPFILE. However, if the COMPATIBLE initialization parameter is set to 11.0.0, the SPFILE can be backed up to disk and cataloged manually at standby sites where backups are written to tape or NetVault Backup media. The additional metadata stored in SPFILE backup sets enables RMAN to identify which database SPFILE is contained in which backup set. Thus, the appropriate SPFILE backup is chosen during restore from tape or NetVault Backup media.

When implementing a strategy that backs up from both Primary and Standby Servers for an Oracle 10.2.x Data Guard environment, consider the accompanying backup-destination strategy, which is detailed in Defining a Backup Destination strategy.

Because RMAN stores backup metadata in the Recovery Catalog, a backup performed from the Primary Database Server to the FRA results in the RMAN backup pieces created during backup being registered in the Recovery Catalog. On the following day, if a backup performed from the Standby Database Server is also performed to the FRA, the RMAN backup pieces created during backup are also registered in the Recovery Catalog.

Later in the week, if a backup of the FRA is performed to NetVault Backup Media Manager from the Standby Database Server, the FRA-to-NetVault Backup Media Manager backup attempts to access backup sets that were created by the Primary Database Server’s backups to the FRA. Because the primary and standby databases do not share the FRA, the FRA-to-NetVault Backup Media Manager backup fails. RMAN attempts to access backup sets on the Primary Database Server that are not accessible from the Standby Database Server that is performing the FRA-to-NetVault Backup Media Manager backup.

Therefore, for Oracle 10.2.x Data Guard environments, Quest recommends that backups to FRA only be performed from either the Primary Database Server or the Standby Database Server, but not both.

In Oracle 11.x Data Guard environments, the Oracle parameter db_unique_name allows the Recovery Catalog to distinguish the origin of backups to the FRA. When selecting FRA-to-NetVault Backup Media Manager backups, RMAN backs up the backup sets in the FRA of the Database Server performing the FRA-to-NetVault Backup Media Manager backup.

For more information on performing backups to NetVault Backup Media Manager, see Setting backup options. For more information on FRA backups, see Flash Recovery Area (FRA) backups.

Back up from Standby only

Starting with Oracle 11.x, backups of datafiles, archived redo log files, Control Files, and SPFILE are interchangeable between the Primary and Standby Database Server. This interchangeability means that all backups can be performed from one of the Standby Database Servers. With this strategy, Plug‑in for Oracle is installed on both the Primary Database Server and at least one of the Standby Database Servers that performs backups. The plug-in must be installed on the Primary Database Server when it is targeted for a restore; that is, if you want to use the backup of the Standby Database Server to recover the Primary Database Server, you need to install the plug-in on the Primary Database Server.

NOTE: Because Oracle 10.2.x only allows the backing up of the datafiles and the archived redo log files to be offloaded to the Standby Database Server while requiring the backups of the Control Files and the SPFILE to be performed on the Primary Database Server, the Back-up-from-Standby-only strategy is not supported for Oracle 10.2.x Data Guard environments.

Deployment

Plug‑in for Oracle’s support in Data Guard environments is restricted to physical standby databases. Logical and Snapshot standby databases are not supported. A physical standby database is a transactionally consistent copy of the production database. All references to standby databases see physical standby databases.

The plug-in supports the following types of Data Guard deployments:

Deploying the plug-in in a Data Guard environment requires that you install the plug-in on the Primary Database Server and at least one of Physical Standby Servers — based on the backup strategy selected. For more information on selecting a backup strategy, see Defining a deployment strategy.

Single-instance to single-instance Data Guard deployment

In a single-instance to single-instance Data Guard deployment, the plug-in is installed on both the Primary and at least one of the Standby Database Servers.