Failure Rate - understanding the threshold

[YuvalKonstanti]

Hello Dynatrace community,

I have a question, I suspect that my Anomaly detection threshold is wrong for increase in failure rate:

I really don't understand the logic of the Absolute and Relative threshold, can you please try to explain it to me?

I don't get why there is a 0% on the Absolute and 50% on the Relative but I think it's not working as I need it to, and I want to understand to what I should change it.

Thank you.

[josef_schiessl · Accepted solution]

Hi,
lets say you have an expected error rate of 10% (based on last x days).

You can now configure two thresholds (absolute and relative) and if both thresholds breach you get an alert.

Configuring an absolute threshold means the percentage is added on the expected percentage.

For example:

20% absolute threshold means when your error rate goes above 30% (10% expected + 20% absolute) you get an alert.

Configuring a relative threshold means the percentage that is added is based on expected failure rate.

For example:

20% relative threshold means when your error rate goes above 12% (10% expected + 20% of the 10%, so 10% + 10% * 0.2) you get an alert.

if you only want to use one of the two thresholds, you just set the other to 0%.

Bascially the two different ways of thresholds allow you to configure alerts either on absolute value on top of current expected error rate or relative to your current expected error rate.

[YuvalKonstanti · Accepted solution]

Helped a lot, thank you for the example!!