I tried creating an alert on a platform resource, the free memory
metric, absolute threshold > 0, with a dampening of 1 every 10 minutes
(see attached images). In the image you can see that it fired 3 times
in 3 minutes (collection interval of 1 minute). This is similar to the
situation I have with a different resource and metric.
Unfortunately the images didn't come through for me, but you may be
seeing the expected behavior. It's not actually "1 *every* 10
minutes", it's "once every X=1 times the condition set is true within a
time period of Y=10 minutes".
That means you get an alert if the condition set matches 1 time within a
10 minute period. If you report every minute you get a chance of up to
10 evaluations. So X can validly be set in a range of [1..10]. Since
you set X=1, only 1 evaluation has to match before you get an alert. So,
you get 10 alerts. If you want to ensure that you only get 1 alert in
10 minutes then you'd need to set X=10, and the condition set would have
to match 10 times before an alert would be sent. But this is equivalent
to the simpler "consecutive times" dampening.
At least this is how I understand it. I could be wrong.
As far as I know there is no dampening mechanism for limiting the number
of alerts sent based solely on time. We do have recovery alert defs,
which means you could fire an alert, then have that alert def disabled
until its recovery alert def fires. But again, I don't think there
exists today a way for a recovery alert def to fire based solely on the
disabled-time of its to-be-recovered alert def.