If a negative value is displayed in a graph, and data returned from polled systems do not return negative values, this symptom may be caused by a counter reaching the top of the 32-bit integer limit at either the OS level or within the up.time datastore. In this scenario, delta math would be performed from a number much lower than the previous result, which may result in a negative value.
If delta math (as described above) is not causing the negative values, there may be a 64-bit counter that up.time is interpreting as a 32-bit counter. In this scenario, any value represented by a figure over 32 bits would automatically roll over to a negative number as a result of Java integer handling.
To help isolate the issue, please contact uptime Support and supply the following information:
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