title: PHP-FPM doesn't write to error log
body: <p>I've just installed a nginx+php-fpm server. Everything seems fine except that PHP-FPM never writes error to its log.</p>
  
  <p>fpm.conf</p>
  
  <pre><code>[default]
  listen = /var/run/php-fpm/default.sock
  listen.allowed_clients = 127.0.0.1
  listen.owner = webusr
  listen.group = webusr
  listen.mode = 0666
  user = webusr
  group = webusr
  pm = dynamic
  pm.max_children = 50
  pm.start_servers = 5
  pm.min_spare_servers = 5
  pm.max_spare_servers = 35
  pm.status_path = /php/fpm/status
  ping.path = /php/fpm/ping
  request_terminate_timeout = 30s
  request_slowlog_timeout = 10s
  slowlog = /var/log/php-fpm/default/slow.log
  chroot = /var/www/sites/webusr
  catch_workers_output = yes
  env[HOSTNAME] = mapsvr.mapking.com
  php_flag[display_errors] = on
  php_admin_value[error_log] = /var/log/php-fpm/default/error.log
  php_admin_flag[log_errors] = on
  </code></pre>
  
  <p>nginx.conf</p>
  
  <pre><code>server
  {
    listen        80 default_server;
    server_name   _;
  
    charset       utf-8;
    access_log    /var/log/nginx/access.log rest;
  
    include       conf.d/drops.conf.inc;
  
    location      /
    {
      root        /var/www/sites/webusr/htdocs;
      index       index.html index.htm index.php;
    }
  
    # pass the PHP scripts to FastCGI server listening on socket
    #
    location      ~ \.php$
    {
      root           /var/www/sites/webusr/htdocs;
      include        /etc/nginx/fastcgi_params;
      fastcgi_index  index.php;
      fastcgi_param  SCRIPT_FILENAME /htdocs/$fastcgi_script_name;
      if (-f $request_filename)
      {
        fastcgi_pass   unix:/var/run/php-fpm/default.sock;
      }
    }
  
    location      = /php/fpm/status
    {
      include        /etc/nginx/fastcgi_params;
      fastcgi_param  SCRIPT_FILENAME $document_root$fastcgi_script_name;
      fastcgi_pass   unix:/var/run/php-fpm/default.sock;
    }
  
    location      = /php/fpm/ping
    {
      include        /etc/nginx/fastcgi_params;
      fastcgi_param  SCRIPT_FILENAME $document_root$fastcgi_script_name;
      fastcgi_pass   unix:/var/run/php-fpm/default.sock;
    }
  
    # redirect server error pages to the static page /50x.html
    #
    error_page    500 502 503 504  /50x.html;
    location      = /50x.html
    {
      root        /usr/share/nginx/html;
    }
  }
  </code></pre>
  
  <p>I've made an erroneous php script and run, and see error output on the web browser. Also nginx error log states stderr output from fpm with the same message. I've check that the user have write (I've even tried 777) permission to the appointed log folder. Even the appointed error.log file has be created successfully by php-fpm. However, the log file is always empty, no matter what outrageous error has been made from php script.</p>
  
  <p>What's going on?</p>
  
  <p>[Found the reason quite a while later]</p>
  
  <p>It was permission. Changed the owner to the sites's users solved the problem.</p>