Configuring Dovecot quota (Maildir++) to work with a workaround.org-style setup

Configuration

1. Backup your /etc/dovecot/*.conf files
2. Analyze what quota limit would be suitable for you (du -hs /home/vmail/example.org/*)
3. Open /etc/dovecot/dovecot.conf and add the plugins "quota" and "imap_quota" and define location of the plugin directory

protocol imap {
  mail_plugins = quota imap_quota
  mail_plugin_dir = /usr/lib/dovecot/modules/imap

4. Jump to the LDA section and add the "quota" plugin:

protocol lda {
  mail_plugins = cmusieve quota

5. Search for "userdb static". This section was defined in the workaround.org howto. Because we want to store quota settings in MySQL, we must add a section which takes precedence over that static section. So add the following section before userdb static:

# SQL database
# http://wiki.dovecot.org/AuthDatabase/SQL
userdb sql {
# Path for SQL configuration file, see /etc/dovecot/dovecot-sql.conf for example
  args = /etc/dovecot/dovecot-sql.conf
}

6. Now jump to the "plugin" section at the end of the file. We define the default quota size in KB here.

plugin {
  quota = maildir:storage=512000

7. As the user database stores things like mail/home directory, group and user IDs too, we have to return them somehow with the SQL query. Next we have to edit the /etc/dovecot/dovecot-sql.conf in order to fetch these fields. Add the following SQL query:

user_query = SELECT 5000 AS uid, 5000 AS gid,'/home/vmail/%d/%n' as home,  concat('maildir:storage=    ', quota_kb) AS quota FROM virtual_users WHERE user = '%n';

So this query basically replaces the "userdb static" section. We select a static user- and group-id, mail home-directory and the quota limit in KB from the field quota_kb which you will have to add to the table virtual_users (type int 11).

Possible field values:

• A NULL-value in the field quota_kb results in the default quota value being used (defined in /etc/dovecot/dovecot.conf)
• A value of "0" (zero) disables quota for that user
• Any other valid number in KB sets quota

Test setup

• Restart Dovecot: /etc/init.d/dovecot restart
• Check your dovecot-deliver.log and be sure mails still get delivered and filtered by sieve.
• In Mozilla Thunderbird, open your mailbox and right-click on the Inbox
• In Properties -> Quota your quota limit should be displayed

Optional: show quota limit in Horde/Imp

1. Open horde/imp/config/servers.php and add this line to your configured server:

   $servers['imap'] = array(
       'quota' => array('driver'=>'courier','params'=>array()),
   

   Source: http://www.dovecot.org/list/dovecot/2007-September/025717.html
2. Logout, login into Imp, quota usage should be displayed on top