How do I disable logging for a rake task?

If you have a cron job, you can redirect output to /dev/null like :

* * * * * rake whatever_task_blah_blah > /dev/null 2>&1

The Rails logger is an ActiveSupport::BufferedLogger object, but can be re-assigned to any other kind of Logger object (or any object that responds to the Logger methods) that you wish, including something like this:

dev_null = Logger.new("/dev/null")
Rails.logger = dev_null
ActiveRecord::Base.logger = dev_null

Put these lines at the top of your Rake task and all logging output will be inexpensively sent to /dev/null, which is best explained by its Wikipedia article.

You can add this to the top of the task:

ActiveRecord::Base.logger.level = 2