Server Ruby on Rails + unicorn + nginx stop responding

Question

My server Rails worker normally, but after 10 minutes without a request its response is a bad gateway. I really think my configurations are in order, but it don't work. I don't have more ideas what to is happening.

That my configurations:

unicorn.rb:

@dir = File.expand_path(File.dirname(__FILE__)) + "/.."

worker_processes 2
working_directory @dir

timeout 10

listen File.join('/tmp/nutrimais.sock')
listen File.join('/tmp/nutrimais_2.sock')

preload_app true# if ENV['RAILS_ENV'] != 'development'

GC.respond_to?(:copy_on_write_friendly=) and
  GC.copy_on_write_friendly = true

check_client_connection false

before_fork do |server, worker|

  Signal.trap 'TERM' do
    puts 'Unicorn master intercepting TERM and sending myself QUIT instead'
    Process.kill 'QUIT', Process.pid
  end

  defined?(ActiveRecord::Base) and
    ActiveRecord::Base.connection.disconnect!
end

after_fork do |server, worker|

  Signal.trap 'TERM' do
    puts 'Unicorn worker intercepting TERM and doing nothing. Wait for master to send QUIT'
  end

  defined?(ActiveRecord::Base) and
    ActiveRecord::Base.establish_connection
end

nginx config:

upstream nutrimais {
    # Path to Puma SOCK file, as defined previously
    server unix:/tmp/nutrimais.sock max_fails=2 fail_timeout=10s;
    server unix:/tmp/nutrimais_2.sock;
}

server {
  listen 80;
  server_name dev.nutrimais.com.br;

  location / {
    autoindex on;
    proxy_set_header X-Real-IP  $remote_addr;
    proxy_set_header X-Forwarded-For $remote_addr;
    proxy_set_header Host $host;
    # time out settings
    proxy_next_upstream http_502 timeout;
    proxy_next_upstream_timeout 0;
    proxy_next_upstream_tries 0;
    proxy_connect_timeout 159s;
    proxy_send_timeout   600;
    proxy_read_timeout   600;
    proxy_buffer_size    64k;
    proxy_buffers     16 32k;
    proxy_busy_buffers_size 64k;
    proxy_temp_file_write_size 64k;
    proxy_pass_header Set-Cookie;
    proxy_redirect     off;
    proxy_hide_header  Vary;
    proxy_set_header   Accept-Encoding '';
    proxy_ignore_headers Cache-Control Expires;
    proxy_set_header   Referer $http_referer;
    proxy_set_header   Host   $host;
    proxy_set_header   Cookie $http_cookie;
    proxy_set_header   X-Real-IP  $remote_addr;
    proxy_set_header X-Forwarded-Host $host;
    proxy_set_header X-Forwarded-Server $host;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_pass http://nutrimais;
  }
}

gemfile:

source 'https://rubygems.org'
gem 'rails', '4.2.4'
gem 'unicorn-rails', '~> 2.2'
gem 'pg'
gem 'mysql2', '~> 0.3.18'
gem 'sass-rails', '~> 5.0'
gem 'uglifier', '>= 1.3.0'
gem 'coffee-rails', '~> 4.1.0'
gem 'duktape'
gem 'jquery-rails'
gem 'turbolinks'
gem 'jbuilder', '~> 2.0'
gem 'bootstrap-sass'
gem 'devise'
gem 'simple_form'
gem 'minitest'
gem "paperclip", "~> 4.3"
gem 'aws-sdk', '< 2.0'
gem 'mail_form', '~> 1.5.0.rc'
gem 'sendgrid-ruby'
gem 'zopim_rails'
gem 'meta-tags'
gem 'ckeditor'
gem 'slick_rails'

group :development do
  gem 'better_errors'
  gem 'binding_of_caller', :platforms=>[:mri_20]
  gem 'quiet_assets'
  gem 'rails_layout'
  gem 'spring-commands-rspec'
  gem 'web-console', '~> 2.0'
  gem 'spring'
end
group :production do
  gem 'therubyracer'
end
group :development, :test do
  gem 'factory_girl_rails'
  gem 'faker'
  gem 'pry-rails'
  gem 'pry-rescue'
  gem 'rspec-rails'
  gem 'rubocop'
  gem 'byebug'
end

group :test do
  gem 'capybara'
  gem 'database_cleaner'
  gem 'launchy'
  gem 'selenium-webdriver'
end

Log while gives bad gateway:

Started GET "/menus" for 127.0.0.1 at 2016-01-20 17:25:17 +0000
I, [2016-01-20T17:25:17.580380 #9]  INFO -- : Processing by MenusController#index as HTML
D, [2016-01-20T17:25:17.904933 #9] DEBUG -- :   [1m[36mMenu Load (322.3ms)[0m  [1mSELECT `menus`.* FROM `menus`  ORDER BY created_at DESC[0m
I, [2016-01-20T17:25:20.006674 #9]  INFO -- : Started GET "/menus" for 127.0.0.1 at 2016-01-20 17:25:20 +0000

It stays in Started GET and not does nothing

Answer 1

I discovery what was happening, the linux firewall killed the connection. When I put the database in the same machine it is worked without trumbles.