I need to start 4 resque workers so i used following command
bundle exec rake environment resque:workers RAILS_ENV=production COUNT=4 QUEUE=* VERBOSE=1 PIDFILE=
You don't want to use the COUNT=n option in production, as it runs each worker in a thread instead of a separate process - which is much less stable.
Official Resque docs:
Running Multiple Workers
At GitHub we use god to start and stop multiple workers. A sample god configuration file is included under examples/god. We recommend this method.
If you'd like to run multiple workers in development mode, you can do so using the resque:workers rake task:
$ COUNT=5 QUEUE=* rake resque:workers
This will spawn five Resque workers, each in its own process. Hitting ctrl-c should be sufficient to stop them all.
Here's the example God monitoring/configuration file that ships with Resque to run multiple processes, and here's an example for monit.