Oracle RAC Dataguard Test

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 cluster 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. For this to happen, it is necessary to keep vigil on whether the Data Guard feature is enabled on the Oracle Cluster database server round the clock. The Oracle RAC Dataguard test helps administrators in this regard!

This test helps administrators determine whether the oracle Data Guard feature is enabled, and if enabled helps figure out the current role of the cluster database server. The test also reveals whether any standby database in the cluster has switched into production role recently.

Target of the test : An Oracle Cluster server on which Data Guard feature is enabled

Agent deploying the test : An internal/external agent

Outputs of the test : One set of results for the target Oracle Cluster database server being monitored.

Configurable parameters for the test
Parameter Description

Test period

How often should the test be executed

Host

The host for which the test is to be configured.

Port

The port on which the server is listening.

Service Name

A ServiceName exists for the entire Oracle RAC system. When clients connect to an Oracle cluster using the ServiceName, then the cluster routes the request to any available database instance in the cluster. By default, the Service Name is set to none. In this case, the test connects to the cluster using the ORASID and pulls out the metrics from that database instance which corresponds to that ORASID. If a valid service name is specified instead, then, the test will connect to the cluster using that Service Name, and will be able to pull out metrics from any available database instance in the cluster.

To know the Service Name of a cluster, execute the following query on any node in the target cluster:

select name, value from v$parameter where name =’service_names’

ORASID

The variable name of the oracle instance.

Username

In order to monitor an Oracle database server, a special database user account has to be created in every Oracle database instance that requires monitoring. A Click here hyperlink is available in the test configuration page, using which a new oracle database user can be created. Alternatively, you can manually create the special database user. When doing so, ensure that this user is vested with the select_catalog_role and create session privileges.

The sample script we recommend for user creation (in Oracle database server versions before 12c) for eG monitoring is:

create user oraeg identified by oraeg

create role oratest;

grant create session to oratest;

grant select_catalog_role to oratest;

grant oratest to oraeg;

The sample script we recommend for user creation (in Oracle database server 12c) for eG monitoring is:

alter session set container=<Oracle_service_name>;

create user <user_name>identified by <user_password> container=current default tablespace <name_of_default_tablespace> temporary tablespace <name_of_temporary_tablespace>;

Grant create session to <user_name>;                                

Grant select_catalog_role to <user_name>;

The name of this user has to be specified here.

Password

Specify the password of the specified database user.

Confirm Password

Confirm the Password by retyping it here.

Detailed Diagnosis

To make diagnosis more efficient and accurate, the eG Enterprise embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test for a particular server, choose the On option. To disable the capability, click on the Off option.

The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled:

  • The eG manager license should allow the detailed diagnosis capability
  • Both the normal and abnormal frequencies configured for the detailed diagnosis measures should not be 0.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Is DG enabled?

Indicates whether/not the Data Guard feature is enabled.

 

The values reported by this measure and its numeric equivalents are mentioned in the table below:

Measure Value Numeric Value
Yes 1
No 0

Note:

By default, this measure reports whether/not the Data Guard feature is enabled. The graph of this measure however, is represented using the numeric equivalents only - 0 or 1.

DB mode

Indicates the current role of the cluster database.

 

The values reported by this measure and its numeric equivalents are mentioned in the table below:

Measure Value Numeric Value
Primary 0
Physical standby 1
Logical standby 2
Snapshot standby 3

Note:

By default, this measure reports the current role of the cluster database. The graph of this measure however, is represented using the numeric equivalents only - 0 to 3.

DB open mode

Indicates the open mode status of the cluster database.

 

 

The values reported by this measure and its numeric equivalents are mentioned in the table below:

Measure Value Numeric Value
Mounted 0
Read write 1
Read only 2
Read only with apply 3

Note:

By default, this measure reports the open mode status of the cluster database. The graph of this measure however, is represented using the numeric equivalents only - 0 to 3.

Is switched

Indicates whether/not the role of the cluster database has switched i.e., whether a production database has switched over to standby database and vice versa.

 

The values reported by this measure and its numeric equivalents are mentioned in the table below:

Measure Value Numeric Value
Yes 1
No 0

Note:

By default, this measure reports whether/not the role of the cluster database has switched. The graph of this measure however, is represented using the numeric equivalents only - 0 or 1.