Is it possible to store the log file by day?

I am curious which log library you are using.

From the standard library it is clear you can do this easily, if you are concerned about size or date:

http://ruby-doc.org/stdlib-1.9.3/libdoc/logger/rdoc/Logger.html#method-c-new

I guess he is using the standard rails logger. How would one apply
this to the standard logger, I can't see in my code where it is
created.

Colin

Can you use logrotate or whatever the OS gives for rotating logs?

Yes I agree you should be using logrotate because most logging in
applications is not rotated by them, but instead by logrotate, this
way you can easily adjust the time between your logging, for example I
rotate all my logs hourly some people do it daily, some monthly. If
this were to happen in every application it would become a pretty
annoying task imo.