Disk Size Imbalance (%) checks if some disks have more space in their failure group disks than others. The space is calculated as a ratio between the size of a disk and the sum of the sizes of its active failure group disks. This ratio is compared for all the disks. The difference in the highest and lowest failure group disk space is reported as a percentage. An imbalance of 10% is acceptable.
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 |
> |
10 |
Not Defined |
1 |
Disk Group %diskGroup% has failure groups with disks of different sizes 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 Size Imbalance 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 Size Imbalance (%) is greater than 10% (by default). Disk groups that have failure groups with disks of different sizes 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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