virtual_delivery:
  driver = appendfile
  envelope_to_add
  return_path_add
  mode = 0600
  maildir_format = true
  create_directory = true
  directory = ${lookup mysql{select smtp from users,domains \
                where localpart = '${quote_mysql:$local_part}' \
                and domain = '${quote_mysql:$domain}' \
                and users.domain_id = domains.domain_id}}
  user = ${lookup mysql{select users.uid  from users,domains \
                where localpart = '${quote_mysql:$local_part}' \
                and domain = '${quote_mysql:$domain}' \
                and users.domain_id = domains.domain_id}}
  group = ${lookup mysql{select users.gid from users,domains \
                where localpart = '${quote_mysql:$local_part}' \
                and domain = '${quote_mysql:$domain}' \
                and users.domain_id = domains.domain_id}}
  quota = ${lookup mysql{select users.quota from users,domains \
                where localpart = '${quote_mysql:$local_part}' \
                and domain = '${quote_mysql:$domain}' \
                and users.domain_id = domains.domain_id}{${value}M}}
  quota_is_inclusive = false
  #quota_size_regex = ,S=(\d+):
  quota_warn_threshold = 75%
  maildir_use_size_file = false
  quota_warn_message = "To: $local_part@$domain\n\
                        Subject: Mailbox quota warning\n\n\
                        This message was automatically generated by the mail delivery software.\n\n\
                        You are now using over 75% of your allocated mail storage quota.\n\n\
                        If your mailbox fills completely, further incoming messages will be automatically\n\
                        returned to their senders.\n\n\
                        Please take note of this and remove unwanted mail from your mailbox.\n"