Testing using the mysql dict for quota storage (dovecot-2.0.12-2_127.el5), and ran into a couple issues. First is a permissions issue:

dovecot: lmtp(26786, dude@test.tld): Error: net_connect_unix(/var/run/dovecot/dict) failed: Permission denied (euid=5000(<unknown>) egid=5000(<unknown>) missing +r perm: /var/run/dovecot/dict, euid is not dir owner)

The file /var/run/dovecot/dict is listed with srw------- perms. I changes the perms to srw----rwx and it works, but I would like to figure out how to configure properly to run with the uid and gid 5000 as this is the user for virtual mail.

The second issue is that two identical rows are created in the mysql database for each user quota. The next message delivered updates both rows. Here is my quota config:

90-quota.conf:

plugin { quota_rule = *:storage=10G quota_rule2 = Trash:storage=+10% } plugin { quota = dict:user::proxy::userquota } dict { userquota = mysql:/etc/dovecot/dovecot-dict-sql.conf.ext }

dovecot-dict-sql.conf.ext:

connect = host=a.b.c.d dbname=mail user=user password=derp map { pattern = priv/quota/storage table = domain_user_quotas username_field = username value_field = bytes } map { pattern = priv/quota/messages table = domain_user_quotas username_field = username value_field = message_count }

The last issue might be a documentation omission. Dovecot warned me that the mysql user did not have DELETE privileges on the quota table:

dovecot: dict: Error: sql dict: commit failed: DELETE command denied to user 'user'@'a.b.c.d' for table 'domain_user_quotas'

The quota dict documentation (at http://wiki2.dovecot.org/Quota/Dict) does not mention DELETE being needed:

MySQL uses the following queries to update the quota. You need suitable privileges.

INSERT INTO table (bytes,username) VALUES ('112497180','foo@spam.dom') ON DUPLICATE KEY UPDATE bytes='112497180'; INSERT INTO table (messages,username) VALUES ('1743','foo@spam.dom') ON DUPLICATE KEY UPDATE messages='1743'; UPDATE table SET bytes=bytes-14433,messages=messages-2 WHERE username = 'foo@spam.dom';