Standard Deviation and Event Rules

[Renato Orgito]

I'm having a hard time figuring out how exactly Standard Deviation criteria works with Event Rules. Say a have an Interface and the Standard Deviation for Utilization is 5%. If I create a rule like that:

 

Violation: Utilization In % > 1 Standard Deviations for 1 hour

 

The violation will happens every time the utilization stays 5% above the normal utilization during one hour but will also happen if it stay below 5%. Or the rule above applies only if it is above the normal rate? If the last is true than the rule below will generate a violation when it stays below 5%?

 

Violation: Utilization In % < 1 Standard Deviations for 1 hour

I would like to clear the alarm only when the rate returns to normal, but is very confuse if that is possible or how I could do that.

Hope someone can help!

[stoma11]

Hello RenatoBR,

 

For a threshold condition such as 'metric M > S standard deviations for duration D in window W' a violation only occurs when the metric value is more than S standard deviations above the baseline.  You'd need to use a violation condition like 'metric M < S standard deviations for duration D in window W' to test for metric values more than S standard deviations below the baseline.

 

The direction of the comparison operator specifies whether you're looking at standard deviations above or below the baseline.

[Renato Orgito]

Thank you. That clarifies things. May I ask if you find this in any Product Documentation? I was unable to find anything.