Failure groups are used to store mirror copies of data, two copies for normal redundancy, three copies for high redundancy. Disk Count Imbalance Variance gives the difference in the failure group disk count for the disk in the disk group with the highest failure group disk count and the disk with the lowest.
It may not be possible for every disk to have the same failure group disk count even when all the failure groups are the same size. However an imbalance of more than one indicates that the failure groups are different sizes.
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 |
|
10.1.0.x; 10.2.0.x; 11.1.0.x; 11.2.0.x |
Every 15 Minutes |
After Every Sample |
>= |
2 |
Not Defined |
1 |
Disk Group %diskGroup% has failure groups with different numbers of disks which may lead to suboptimal space usage. Changing the configuration may alleviate this problem. |
For this metric you can set different warning and critical threshold values for each "Disk Group" object.
If warning or critical threshold values are currently set for any "Disk Group" object, those thresholds can be viewed on the Metric Detail page for this metric.
To specify or change warning or critical threshold values for each "Disk Group" object, use the Edit Thresholds page. See Editing Thresholds for information on accessing the Edit Thresholds page.
Disk Count Imbalance Variance is calculated using the V$ASM_DISKGROUP_STAT and V$ASM_DISK_STAT views, along with some internal ASM fixed tables.
A warning alert will be generated when the Disk Count Imbalance Variance is greater than 1 (by default). Disk groups that have failure groups with different numbers of disks may lead to suboptimal space usage. To alleviate this problem, try changing the configuration.
Related Topics
About Alerts
About the Metric Detail Page
Editing Thresholds
Understanding Line Charts
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