Dovecot

1. Create a maildir called newsletters

2. Entered this to define the namespace in dovecot.conf

namespace public {
  separator = /
  prefix = newsletters/
  list = yes
  subscriptions = yes
  location = maildir:/home/public/newsletters
}

3. quota3 = maildir:Public quota:ns=newsletters/

4. quota3_rule = *:storage=100M