The average latency in milliseconds of a synchronous single-block read. Synchronous single-block reads are a reasonably accurate way of assessing the performance of the storage subsystem. High latencies are typically caused by a high I/O request load. Excessively high CPU load can also cause the latencies to increase.
The rest of the information in this section is only valid for this metric when it appears in either the Enterprise Manager Grid Control or the Enterprise Manager Database Control (if applicable).
The following table shows how often the metric's value is collected and compared against the default thresholds. The 'Consecutive Number of Occurrences Preceding Notification' column indicates the consecutive number of times the comparison against thresholds should hold TRUE before an alert is generated.
|
Target Version |
Evaluation and Collection Frequency |
Upload Frequency |
Operator |
Default Warning Threshold |
Default Critical Threshold |
Consecutive Number of Occurrences Preceding Notification |
Alert Text |
|
11.1.0.x; 11.2.0.x |
Not Defined |
After Every Sample |
> |
Not Defined |
Not Defined |
2 |
Not Defined |
v$sysmetric
First, verify that your storage subsystem is not operating with component failures, for example, disk, network, or HBA failures. If no issues are found, consider upgrading your storage subsystem.
Related Topics
About Alerts
About the Metric Detail Page
Editing Thresholds
Understanding Line Charts
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