Another way to limit the notifications sent is trigger dependencies, which come in really handy here. If a trigger that is dependent on an already active trigger fires, we have seen the effect on the frontend—the dependent trigger did not appear in the list of active triggers. This is even better with actions; no action is performed in such a case. If you know that a website relies on a Network File System (NFS) server, and have set a corresponding dependency, the NFS server going down would not notify you about the website problem. When there's a problem to solve, not being flooded with emails is a good thing.

There's a possible race condition if the item for the dependent trigger is checked more often. In such a case, the dependent trigger might fire first, and the other one a short time later, thereby still producing two alerts. While this is not a huge problem for the trigger displaying in the frontend, this can be undesirable if it happens when actions are involved. If you see such false positives on a frequent basis, change the item intervals so that the dependent one always has a slightly longer interval.