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As a PRTG User, I want to be able to be alerted on changes in the value of a sensor, but only changes that meet a certain threshold.
Details of User Story
Imagine a sensor that returns bytes consumed, or the number of rows in a table. In this case, I fully expect the values to change regularly, so every change in value isn't meaningful. While in many cases it is useful to be notified when a specific threshold is hit, in other situations it is far more meaningful to know when a jump in values occurs. It may be normal for several GB of space to be consumed each day, but if all of a sudden 100 GB additional gets consumed, i would want to be alerted of that fact. The specifics would be the ability to specify an alert when a specified percentage change occurs over a specific period of time. Even if it were only able to detect a percentage change from the last reading, that could also work, but in that case you'd need to set your interval and percentage to something that has meaning.
My needs would be met if I were able to get an alert condition to fire (either Warning or Error, which could then be emailed) whenever a sensor, returning a number, changes (up or down) more than a specified percentage of the previous value, OR when the sensor value changes (up or down) more than a specified percentage of the average of the readings over the past window of time (that I would also be able to specify).
It would also be acceptable to specify a hard value instead of percentage. Obviously, it would be best if I could do either. So, to use my example of table rows, I could specify if the number of table rows (as returned by the sensor) changes my more than 10,000 in any given period, rather than specifying a percentage of the previous readings of table rows.
Thanks for your consideration.