eG Monitoring
 

Measures reported by OraRacVIPStTest

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 OraRacVIPStTest.

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.

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.

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
NumberOfScanVIPs Indicates the number of SCAN VIPs associated with this node. Number  
IsScanVIPEnabled Indicates whether the SCAN VIP is enabled on this node.   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 the above-mentioned 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.
IsScanVIPRunning Indicates whether/not the SCAN VIP is running on this node.   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 the above-mentioned 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.
ScanVIPRelocated Indicates whether/not any SCAN VIP is relocated to this node.   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 the above-mentioned Measure Values displayed in the table above to indicate whether the SCAN 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.