Using naxsi as a "circuit breaker"

[Cyrus]

I only know the basics of naxsi, but bare with me.

I want to automatically have virtual hosts blocked when they are getting
too many new requests. I can't find information on solving this
particular problem with it. It might be that naxsi isn't even the best
solution. I want to define virtual hosts and how many requests they can
have in a second, or some other unit of time.

It would be useful because I run a shared webserver, with quite a few
people using it. I had issues recently with a site leaping into
popularity. This causes resource constraints and lots of 500 internal
errors, breaking the server for other customers. This was not a DDOS attack.