Rails 3.2 feature: unreadable production logs(github.com)

    file = File.open("log/production.log", "w")
    file.sync = true
    Rails.logger = ActiveSupport::BufferedLogger.new(file)

    config.after_initialize do
      # Reverse the deprecation of flush in BufferedLogger
      module ActiveSupport
        class BufferedLogger
          def flush
            @log_dest.flush
          end
          def respond_to?(method, include_private = false)
            super
          end
        end
     end
     # Let the OS buffer the log
       Rails.logger.instance_variable_get(:@logger).instance_variable_get(:@log_dest).sync = false
    end

  ActiveSupport::BufferedLogger#auto_flushing is deprecated.  Either set the
  sync level on the underlying file handle like this:

        f = File.open('foo.log', 'w')
        f.sync = true
        ActiveSupport::BufferedLogger.new f

  Or tune your filesystem.  The FS cache is now what controls flushing.