Big Work Loads & Concurrency

I am just learning Ruby and planning a to use it for a network
monitoring system. I would like to design a system that will scale well
and handle large work loads ( tens of thousands of monitors per server
). My question is about concurrency. I am looking at threads and have
fiddled with them a bit. Ruby makes threading pretty straight forward.
Now I’m trying to figure how to best use them. The design goal is to
have a server host tens of thousands of monitors in the most efficient
way. Monitors will need to be executed at specific and varying
intervals. (i.e. 1000 monitors once a minute / 2000 monitors once every
three minutes / 5000 monitors once every 5 minutes / 10,000 monitors
once every 10 minutes, etc.)

This is a problem that I’m sure has already been solved. I would
appreciate any suggestions that the group can offer regarding a proven
design to tackle this goal.

Thanks, Don