unicorn.rb

after_fork do |server, worker|
  port = 5000 + worker.nr
  child_pid = server.config[:pid].sub('.pid', ".#{port}.pid")
  system("echo #{Process.pid} > #{child_pid}")
  defined?(ActiveRecord::Base) and
    ActiveRecord::Base.establish_connection

  #one log per unicorn worker
  filepath = "#{root}/log/#{Rails.env}.#{worker.nr}.log"

  f = File.open filepath, 'a'
  f.binmode
  f.sync = true

  Rails.logger.instance_eval do
    level = @logger.level
    @logger && @logger.flush && @logger.close
    @logger = ActiveSupport::BufferedLogger.new(f, level)
  end
end