[mistwang]

Can't this be prevented? I find it worrying that someone can create insane numbers of processes with this kind of behaviour. Especially with the high RAM requirements of Rails it is very easy to DOS a small server this way.

We will improve the process manager see if we can come up with a better solution. This kind of attack can be easily fend off with our request rate throttling feature.

Yes, it doesn't create more than 3 children when I use ab -c 10. But it kills all but one after the requests are finished. Is there some way of keeping the processes alive?

That's because "ab" cancels the extra requests it sent at the end of the test. If you try "ab -c 1", the child process is alive at the end.