Hi Fernando,
DA values work like this
0 – No data
10 – Everything normal
Anything greater than that till 40 indicates varying degrees of breach.
So, you will never have value less than 10 unless its no-data (count is 0) in original metric
From the images attached, I am not able to see where ART is dropping to zero.
The first image indicates ART pretty stable with one spike which is reflected by one tiny bump there in variance intensity. DA is quite good in catching up to latest values so if your application is varying between 100 and close to zero and it is expected behavior eventually it will catch up, but depending on how often these two ranges are used it may take a while (since deviation and variance is affected by values in distribution)
This is what I can guess is happening. ART normally is always 100, no major deviation so it’s very less. Sometimes ART drops to 10 or stay there and DA learns in few cycles and now the prediction is around the same value. Since the values are not deviating much (yet), our band for triggering will be very close to around 10, like 15 or so. So, when it climbs back to normal 100 again, this is a change for DA now since its higher than what was expected so triggers alert. Over time if we have a healthy combination of 10, and 100 values the deviation is going to grow little higher to cover both ranges hopefully.
This may not help much so you can configure the control to act little more conservative in triggers. To do this you can modify some knobs in DC.
You can increase caution and danger threshold from current values to higher values by moving sliders right. This means we will wait for more breaches before increasing variance intensity. The more right we go, the more conservative we get.
Other controls in advanced could help; but let’s come back to it only when needed.
This page in docops should give reasonable idea on what each control does
https://docops.ca.com/ca-apm/10-5/en/administrating/manage-metric-data-by-using-management-modules/configure-differential-analysis
Hope it helps
Regards,
Sergio