[Dovecot] Per-user quota (with local users)

[Maykel Moya]

I'm migrating to LDAP mi local users, there is the auth section of my
dovecot.conf

--
auth default {
  mechanisms = plain

  socket listen {
    master {
      path = /var/run/dovecot/auth-master
      mode = 0660
      user = dovecot
      group = nusers
    }
  }

  passdb ldap {
    args = /etc/dovecot/dovecot-ldap.conf
  }
  
  passdb pam {
  }
  
  userdb ldap {
    args = /etc/dovecot/dovecot-ldap.conf
  }
  
  userdb prefetch {
  }
  
  userdb passwd {
  }
  
  user = root
}
--

The idea is to try to find the user in the directory and if it isn't
found then fallback to a local user lookup.

My quota configuration is
--
plugin {
  quota = maildir:storage=10240:ignore=Trash
}
--

I have some users with particular quotas. With LDAP lookups, there is no
problem, in those cases I simply put their particular quota values in
their entries and pass it to dovecot via user_attrs.

I wonder how to do the same for local users, I mean, to have the ability
of specifying particular quotas for some local users.

Another doubt is how to express to Dovecot that a user have no quota at
all, could I use 0?

Regards,
maykel