Would you mind to try Nginx caching in Plesk Onyx 17.8 Preview?
This would be very helpful to get your experienced feedback here http://www.surveygizmo.com/s3/4165754/Plesk-17-8-Preview
64 votesopen discussion · 4 comments · Feature Suggestions » Web / HTTP functions · Flag idea as inappropriate… · Admin →Michael commented
It would also be very handy to be able to select the log format or at least alter it or define a custom one like
log_format timed_combined '$remote_addr - $remote_user [$time_local] '
'"$request" $status $body_bytes_sent '
'"$http_referer" "$http_user_agent" '
This includes the variables $request_time and $upstream_response_time while everything else is default. Right now, there is no possibility to add this information to the access log.