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Checkmk polls all monitored hosts within the configured normal check interval (by default once a minute).
If the service then enters a not-OK-state, Checkmk uses the retry interval to re-check (again, once a minute by default).
If the endpoint is DOWN, Checkmk regularly tries to poll the agent, needs to wait for the timeout (10 seconds by default) before it aborts this try.
This binds a fetcher process for the mentioned amount of time and hence decreases your monitoring performance.
This problem multiplies with the number of endpoints monitored.
Related reading: How-to adjust Checkmk performance
Downtimes
As mentioned before, your endpoints will be DOWN a good part of the day on average. Hence, you need to think about your monitoring operation.
Typically, your hosts are UP all day every day, and you want your monitoring to notify you the moment this changes. And if you do some planned maintenance, you schedule a downtime.
For endpoints this will not work as easily: Downtimes do not solve the aforementioned performance issues, as monitoring continues through downtimes. And you will not be able to keep track of manually schedule them for your hosts.
Read below for possible approaches to solve this problem.
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