A reiteration from Schwuk - log rotation in Ruby on Rails is as simple as an extra line in your config/environment.rb file:

RAILS_DEFAULT_LOGGER = Logger.new("#{RAILS_ROOT}/log/#{RAILS_ENV}.log", 20, 10.megabyte)

I put this line right BEFORE the Rails::Initializer.The above line will automatically rotate your logs when they hit 10 megabytes, and it will keep the 20 most recent logfiles.

The details of this mechanism can be found in the Logger standard Ruby library. Specifically:

1. Create a logger which ages logfile once it reaches a certain size. Leave 10 “old log files” and each file is about 1,024,000 bytes.

   logger = Logger.new('foo.log', 10, 1024000)

2. Create a logger which ages logfile daily/weekly/monthly.

   logger = Logger.new('foo.log', 'daily')
   logger = Logger.new('foo.log', 'weekly')
   logger = Logger.new('foo.log', 'monthly')