fastcgi_limit_rate

This directive appeared in version 1.7.7.

Limits the speed of reading the response from the FastCGI server. The rate is specified in bytes per second. The zero value disables rate limiting. The limit is set per a request, and so if nginx simultaneously opens two connections to the FastCFI server, the overall rate will be twice as much as the specified limit. The limitation works only if buffering of responses from the FastCGI server is enabled.