[cperciva]

If you have N requests hitting Apache and one of them is slow, that one slow request will run in its own process while the fast requests are sent off to other processes. The fact that each process only handles one request at once is irrelevant.

[tptacek]

Uh, this is how Rails setups work too. You aren't talking directly to Mongrel.

[cperciva]

Maybe I misunderstood the article -- it sounded to me like requests were being distributed between Mongrel processes and queued on the individual processes rather than being queued centrally and only allocated to individual processes when a process is free (like Apache does).

[davidw]

The problem with Mongrel is that you allocate N mongrel instances at setup time. Apache, on the other hand, can dynamically allocate new processes (up to a limit) in order to meet increased demand. This is especially important for people like me, who host more than one site on a machine, and want to be able to handle load up to a certain point without fiddling with config files every time there is a spike in traffic.

[rantfoil]

That's correct -- the load balancer passes the traffic directly to Mongrel, and each mongrel has its own internal queue / mutex.

That's why you run like 4 or 8 or 12 or N many mongrels to handle additional load.