Quota
=====

There are different quota backends that Dovecot can use:

 * <fs> [Quota.FS.txt]: Filesystem quota.
 * <dirsize> [Quota.Dirsize.txt]: The simplest, but sometimes slow, quota
   backend. It scans all the files from mail directories to calculate the
   quota.
 * <dict> [Quota.Dict.txt]: Store quota in a dictionary (table).
 * <maildir> [Quota.Maildir.txt]: Maildir++ quota.

There are currently two quota related plugins:

 * quota: Implements the actual quota handling and includes also all the quota
   backends.
 * imap_quota: For reporting quota information via IMAP.

Usually you'd enable these by adding them to the 'mail_plugins' settings in the
config file:

---%<-------------------------------------------------------------------------
protocol imap {
  mail_plugins = quota imap_quota
}
protocol pop3 {
  mail_plugins = quota
}
# In case you're using deliver:
protocol lda {
  mail_plugins = quota
}
---%<-------------------------------------------------------------------------

Most of the quota backends have a few things in common:

You can set the quota as kilobytes (called *storage*) and/or as number of
messages (called *messages*). Usually only the *storage* quota is used. These
limits can be given to the quota backend as parameters, e.g.:

---%<-------------------------------------------------------------------------
plugin {
  # 10 MB quota limit
  quota = maildir:storage=10240
  # 1000 messages quota limit
  quota = maildir:messages=1000
  # 10 MB + 1000 messages quota limit
  quota = maildir:storage=10240:messages=1000
}
---%<-------------------------------------------------------------------------

The above example shows how to set the same quota globally for everyone. You
can override this for one or all users by returning a 'quota' <extra field>
[UserDatabase.ExtraFields.txt] from the user database (in the exact same format
as above). See<UserDatabase.txt> for more information about how to set them for
the user database you are using.

Examples
--------

SQL
---

---%<-------------------------------------------------------------------------
# MySQL:
user_query = SELECT home, uid, gid, concat('maildir:storage=', quota_kb) AS
quota FROM users WHERE userid = '%u'
# PostgreSQL, SQLite:
user_query = SELECT home, uid, gid, 'maildir:storage=' || quota_kb AS quota
FROM users WHERE userid = '%u'
---%<-------------------------------------------------------------------------

LDAP
----

---%<-------------------------------------------------------------------------
# quotaStorage must be in the format mentioned above
# For example: maildir:storage=10240
user_attrs = homeDirectory=home,uidNumber=uid,gidNumber=gid,quotaStorage=quota

# If you have the quota already as kilobytes in LDAP, there's a kludgy way to
use it directly:
user_attrs =
homeDirectory=home,uidNumber=uid,gidNumber=gid,quotaStorage=quota=maildir:storage
---%<-------------------------------------------------------------------------

If you have the quota stored as bytes, you'll need to use a <post-login
scripting> [PostLoginScripting.txt] trick to use them. Something like:

---%<-------------------------------------------------------------------------
# quotaStorage contains the quota in bytes. It's exported into
# $QUOTA_BYTES environment.
user_attrs =
homeDirectory=home,uidNumber=uid,gidNumber=gid,quotaStorage=quota_bytes
---%<-------------------------------------------------------------------------

And make imap's 'mail_executable' point to a script:

---%<-------------------------------------------------------------------------
#!/bin/sh

export QUOTA=maildir:storage=`expr $QUOTA_BYTES / 1024`
exec /usr/local/libexec/dovecot/imap
---%<-------------------------------------------------------------------------

(This file was created from the wiki on 2007-06-15 04:42)