This metric shows the read throughput detail of a disk group mounted in an Automatic Storage Management (ASM) instance. This gives an indication for the total number of bytes read from the disk group with proportion to the total read time for this disk group in an instance.
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.
|
Target Version |
Collection Frequency |
|
All Versions |
Every 15 Minutes |
It is calculated using the Instance Disk Performance metric which in turn collects data from the GV$ASM_DISKGROUP and GV$ASM_DISK views for 10g Release 1 and the GV$ASM_DISKGROUP_STAT and GV$ASM_DISK_STAT views for 10g Release 2.
To calculate the average read throughput of each disk, the total number of bytes read is divided by the total read time during the collection interval. This data is aggregated by the disk group name to get the average read throughput of a disk group. The data is then aggregated for all instances that are part of the cluster.
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Related Topics
About Alerts
About the Metric Detail Page
Editing Thresholds
Understanding Line Charts
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