Here's some good info regarding Core and Mod-Gearman if you haven't seen it:https://www.youtube.com/watch?v=vHieG_kZ7rEhttps://www.youtube.com/watch?v=KJjEtn3bmPc
Here's our documentation for Nagios XI, which is pretty applicable to Core as well:https://assets.nagios.com/downloads/nag ... ios_XI.pdf
A lot of these questions are answered here:https://labs.consol.de/nagios/mod-gearman/index.html
Does Mod-Gearman supports Nagios Core 4. I'm using Nagios core 4.0.8 and 4.1.1
From the developers:Mod-Gearman 3.x works with Nagios 3 and Naemon (and might work with Nagios 4)
What is the worker capacity in terms of host or service counts.
It would depend heavily on the types of checks being run. Compiled C runs a lot faster than Perl, for example.
What is the maximum count of worker can be connected to a single Nagios.
There aren't any hard-caps, though the workers work through the Gearman server; The workers don't talk to Nagios directly.