quota-status fails when size=0 from Postfix

[dovecot at ptld.com]

> and since dovecot does not know postfix virtual aliases is would make
> sense dovecot also support postfix virtual aliases in dovecot quota
> service

Why not? You can create a query telling dovecot to lookup the quota of 
the mailbox the alias points to. Ofcourse your tables wont look like 
mine but this example can give you an idea of how to set it up.

   SELECT accounts.inbox AS user, CONCAT('*:storage=', 
accounts.diskQuota, 'm') AS quota_rule
   FROM aliases
   LEFT JOIN accounts USING(email)
   WHERE aliases.alias = '%u' AND accounts.email IS NOT NULL LIMIT 1

You setup multiple userdb{} as fall backs. If your first query looking 
up email accounts doesn't find a match it processes the next userdb{} in 
line which would be a query looking for a match in aliases.