Oracle RAC Scan VIP Status Test

Oracle Database clients connect to the database using a Single Client Access Name (SCAN). The SCAN is associated with the entire Oracle cluster, rather than an individual node, and associated with multiple IP addresses instead of a single address. The SCAN resolves to multiple IP addresses reflecting multiple listeners in the cluster that handle public client connections. When a client submits a request, the SCAN listener listening on a SCAN VIP address and the SCAN port are made available to a client. Since all services on the cluster are registered with the SCAN listener, the SCAN listener replies with the address of the local listener on the least-loaded node where the service is currently being offered. Finally, the client establishes connection to the service through the listener on the node where service is offered. All of these actions take place transparently to the client without any explicit configuration required in the client. Also, the client’s connect information does not need to change if you add or remove nodes or databases in the cluster.

The SCAN listeners can be made available only if the SCAN VIPs are enabled and running in the database instances. The SCAN VIPs also load balances across the instances providing a service, by selecting and routing requests to the least loaded node. For a user request to be processed seamlessly, it is important for a node to be available round the clock! In case of failures, the node should be automatically relocated to a different SCAN VIP. To identify the SCAN VIP on which a node has been relocated and also to identify the SCAN VIPs that are not enabled and are not running, administrators can use the Oracle RAC SCAN VIP Status test.

This test auto-discovers the nodes in the target Oracle Cluster, and for each node reports the count of SCAN VIPs. This test also helps administrators identify whether/not each SCAN VIP is enabled/running. Also, this test helps administrators identify the SCAN VIP on which a node has been relocated to in case of a SCAN VIP failover.

Target of the test : An Oracle Cluster

Agent deploying the test : An internal agent

Outputs of the test : One set of results for each instance on the Oracle Cluster being monitored.

This test also reports a set of results for Summary descriptor.

Configurable parameters for the test
Parameters Description

Test period

How often should the test be executed. By default, this is set to 60

Host

The IP address of the Oracle server.

Port

The port number through which the Oracle server communicates. The default port is 1521.

DD Frequency

Refers to the frequency with which detailed diagnosis measures are to be generated for this test. The default is 1:1. This indicates that, by default, detailed measures will be generated every time this test runs, and also every time the test detects a problem. You can modify this frequency, if you so desire. Also, if you intend to disable the detailed diagnosis capability for this test, you can do so by specifying none against DD frequency.

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

Scan VIP count

Indicates the number of SCAN VIPs associated with this node.

Number

 

Is scan VIP enabled?

Indicates whether the SCAN VIP is enabled on this node.

 

The values that this measure reports and their corresponding numeric values are as follows:

Measure Value Numeric Value
Yes 1
No 0

Note:

By default, this measure reports the Measure Values displayed in the table above to indicate whether SCAN VIP is enabled on each instance. The graph of the measure, however, is represented using the corresponding numeric equivalents - i.e., 0 and 1.

Is scan VIP running?

Indicates whether/not the SCAN VIP is running on this node.

 

The values that this measure reports and their corresponding numeric values are as follows:

Measure Value Numeric Value
Yes 1
No 0

Note:

By default, this measure reports the Measure Values displayed in the table above to indicate whether SCAN VIP is running on each instance. The graph of the measure, however, is represented using the corresponding numeric equivalents - i.e., 0 and 1.

Is scan VIP relocated?

Indicates whether/not any SCAN VIP is relocated to this node.

 

The values that this measure reports and their corresponding numeric values are as follows:

Measure Value Numeric Value
Yes 1
No 0

Note:

By default, this measure reports the Measure Values displayed in the table above to indicate whether the VIP is relocated. The graph of the measure, however, is represented using the corresponding numeric equivalents - i.e., 0 and 1.

The detailed diagnosis of this measure reveals the names of previous and current nodes of the SCAN VIP.