Oracle RAC Cluster Nodes Test

This test reports the count of nodes in the Oracle cluster and indicates the number and names of those nodes that are currently accessible. This way, the nodes that are inaccessible/unavailable can be identified. The test also reports the percentage of available nodes, and thus indicates if only very few nodes in the cluster are able to service the client requests to the cluster. This signals a potential overload.

Target of the test : Oracle RAC

Agent deploying the test : An external agent; if you are running this test using the external agent on the eG manager box, then make sure that this external agent is able to communicate with the port on which the target Oracle cluster is listening. Alternatively, you can deploy the external agent that will be running this test on a host that can access the port on which the target Oracle cluster is listening.

Outputs of the test : One set of results for every SID (instance) monitored..

Configurable parameters for the test
  1. TEST PERIOD - How often should the test be executed.
  2. Host – The host for which the test is to be configured.
  3. Port - The port on which the server is listening.
  4. orasid - The variable name of the oracle instance.
  5. 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 ServiceName of a cluster, execute the following query on any node in the target cluster:

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

  6. User – 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.

  7. Password – Password of the specified database user
  8. Confirm password – Confirm the password by retyping it here.
  9. ISPASSIVE – If the value chosen is yes, then the Oracle server under consideration is a passive server in an Oracle cluster. No alerts will be generated if the server is not running. Measures will be reported as “Not applicable’ by the agent if the server is not up.
  10. timeout - Specify the duration (in seconds) beyond which the test will timeout if no response is received from the server. The default value is 30 seconds.
  11. To make diagnosis more efficient and accurate, the eG Enterprise suite 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

Total nodes:

Indicates the number of nodes in the cluster.

Number

 

Available nodes:

Indicates the number of nodes in the cluster that are currently accessible.

Number

Use the detailed diagnosis of this measure to know which nodes in the cluster are currently accessible.

Unavailable nodes:

Indicates the number of nodes in the cluster that are currently unavailable.

Number

 

Percentage of available nodes:

Indicates the percentage of nodes in the cluster that are available.

Percent

A high value is desired for this measure.