Is a main disconnect required at a sub-panel which contains more than 6 circuit breakers, is located within the same building and is not part of the service equipment?
To that, let me add that you will need the breaker at the main panel to protect both the feeder to the subpanel and the subpanel itself. In other words, if the subpanel is rated at 60 amps, then the breaker at the main panel cannot be a 100 amp breaker, even if the feeder is capable of handling 100 amps.