Finally I upgraded my nagios 2.x to 3.x and now I have problems with max_concurrent_checks.
I have external script, that periodically (executed by nagios active check) submit about 1500 passive checks results.
Before upgrade I have max_concurrent_checks=15 and was happy, now after upgrade maximum concurrent checks affects not only active check count running in parallel, but also it affect processing of passvice checks results. In log many:
Max concurrent service checks (15) has been reached. Delaying further checks until previous checks are complete..
I think, this is wrong behavior.
Now I set max_concurrent_checks=5000 for temp solution, but I have many active checks that overload my cpu.
What should I do?