Remote Icinga instance is not connectet to master - for a few minutes after reload

[log1c]

Can’t help you specifically, but I remembered this thread:

Icinga2 at large scale

Hello community, I was not sure where to put this topic, please move it if it’s under wrong category In this topic i would like to cover several questions: system requirements, possible bottlenecks and benchmarking. Hope this will simplify installation for new users and provide “ready for deploy” cluster schemas and strategy. My main goals are: define benchmarking tools for stress testing of cluster prototype define how scalable Icinga2 is, based on stress tests provide system requirements …

There were some test run there by one/some user(s), but I think it was mostly focused on the IDO database.
But maybe there is something helpful for you inside there as well.