We are using nginx for file uploads instead of directing to the backend servrs. Used lua openresty module to get the data in chunks in write it to local disk. File size could vary from few KB's to 10MB.

We are tuning worker process, connections, accept_mutex off etc, but if we cuncerrently upload files some of the connections were very slow.

Chuck size is 4096. CPU utilization is very minimal. We are running 10 worker processes, but most of the cases sam process is handling multiple connections and they are becoming slow. Please suggest the best possible configuration for upload scenarios