Maxim Dounin Wrote:
> If you want to change nginx configuration - just add
> $upstream_cache_status variable to a log, it will show if a
> response was from nginx cache (HIT) or was requested from a
> backend.
>
> Other upstream-related variables may be interesting too, in
> particular $upstream_response_time. See here for more:

I add new log_format in /etc/nginx/nginx.conf:
log_format main '$remote_addr - $remore_user, $upstream_cache_status : $upstream_response_time'

and assign this formatter to access.log.

On several times running on "caches/fast" site output is:
192.168.111.254 - -, - : 0.090
192.168.111.254 - -, - : 0.044
192.168.111.254 - -, - : 0.054
192.168.111.254 - -, - : 0.057
192.168.111.254 - -, - : 0.047
192.168.111.254 - -, - : 0.049
192.168.111.254 - -, - : 0.053

wait some time (~2 mins), run again, and another string:
192.168.111.254 - -, - : 23.998