To be more specific the fastcgi cache is not working. I use it this way:
fastcgi_cache_path /tmp levels=1:2
keys_zone=NAME:10m
inactive=5m;
fastcgi_cache_key "$scheme$request_method$host$request_uri";
fastcgi_cache_path /tmp levels=1:2
keys_zone=NAME:10m
inactive=5m;
fastcgi_cache_key "$scheme$request_method$host$request_uri";