The sudden dip in the charts occur because the counters holding the values displayed in the charts can contain at most 231 (2147483648) integers. The counters revert back to zero after reaching 231 (2147483648) integers. Then, they continue to go up again. The counters do not usually display zero in a chart because they are quickly gathering data again.
The following charts for individual drives are impacted: ReadIOs, WriteIOs, TotalIOs, Bytes Transferred, Unrecovered Errors, Recovered Errors, Timeouts, Retried Requests
The following charts for individual volumes are impacted: Bytes Read, Bytes Read Large, Bytes Written, Bytes Written Large, ReadIOs Large, WriteIOs Large, ReadIOs, WriteIOs, TotalIOs, Bytes Transferred, ReadHitIOs
Values Continue to Increase in Charts for Aggregated Drives and Aggregate Volumes
Values in charts for aggregate drives and aggregate volumes continue to rise smoothly in Performance Manager and on the Monitoring tab. The only time the values in the charts come back down to the values returned by the array, is when the service for the management server restarts. Then, the charts display the values returned by the array. The values in the charts continue to rise until the service for the management server is stopped.
The values in the charts continue to rise because the values do not revert back to zero when an individual drive or volume counter that makes up the aggregation contain 231 (2147483648) integers. Instead, the values continue to rise smoothly.
The following charts for aggregate drives are impacted and charts for aggregated drives are also provided for arrays, controllers, and volume groups: ReadIOs, WriteIOs, TotalIOs, Bytes Transferred, Unrecovered Errors, Recovered Errors, Timeouts, Retried Requests
The following charts for aggregate volumes are impacted, and charts for aggregated volumes are also provided for arrays, controllers, and volume groups: Bytes Read, Bytes Read Large, Bytes Written, Bytes Written Large, ReadIOs Large, WriteIOs Large, ReadIOs, WriteIOs, TotalIOs, Bytes Transferred, ReadHitIOs
Storage Essentials 5.00.01 User Guide 513