> "The temperature is on a trajectory to breach the machine's operating limit in N minutes" seems pretty actionable. Do you really think that the folks in the

> "The temperature is on a trajectory to breach the machine's operating limit in N minutes" seems pretty actionable. Do you really think that the folks in the Google datacenters are not monitoring rack temp? Implemnting Symptom based alerting does not mean you should not be monitoring other system metrics. Their monitoring system probably filed a P1 or P2 ticket for someone to go take a look at it at some point. But should a person be paged at 2 A.M to repair this? Absolutely not.