This documentation is for Dovecot v2.x, see wiki1 for v1.x documentation.
Differences between revisions 1 and 33 (spanning 32 versions)
Revision 1 as of 2005-10-28 15:35:03
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Editor: TimoSirainen
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Revision 33 as of 2010-07-29 15:09:49
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Comment: Added info for loading the quota plugins in 2.0 and addtional hint if plugin is not loaded
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== Filesystem quota == = Quota =
Quota backend specifies the method how Dovecot keeps track of the current quota usage. They don't (usually) specify users' quota limits, that's done by returning extra fields from userdb. There are different quota backends that Dovecot can use:
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Dovecot doesn't work too well with filesystem quota currently. But there are a few things you can do:  * [[Quota/FS|fs]]: Filesystem quota.
 * [[Quota/Dirsize|dirsize]]: The simplest and slowest quota backend, but it works quite well with mboxes.
 * [[Quota/Dict|dict]]: Store quota usage in a dictionary (e.g. SQL).
 * [[Quota/Maildir|maildir]]: Store quota usage in Maildir++ maildirsize files. This is the most commonly used quota for virtual users.
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 * Set index file location to some partition where there are no quota limits. Dovecot can't currently handle out-of-quota error conditions when updating indexes.
 * mbox should work somewhat nicely as long as `mbox_lazy_writes=yes` in config file. Although if user doesn't delete any mails when closing the mailbox, Dovecot gives an "internal error".
 * Maildir also needs to update `dovecot-uidlist` file, which can't handle out-of-quota errors. Its location can be set using "CONTROL" parameter in default_mail_env.
== Enabling quota plugins ==
There are two quota related plugins:
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So, use something like:  * quota: Implements the actual quota handling and includes also all the quota backends.
 * imap_quota: For reporting quota information via IMAP.

Enable them in dovecot.conf:
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# mbox:
default_mail_env = mbox:%h/mail:INBOX=/var/mail/%u:INDEX=/var/no-quotas/index/%u
mail_plugins = $mail_plugins quota
protocol imap {
  mail_plugins = $mail_plugins imap_quota
}
}}}
'''Info:''' with Dovecot 2.0 you can enable the quota plugin also in 10-mail.conf instead of the global dovecot.conf:
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# maildir:
default_mail_env = maildir:%h/Maildir:INDEX=/var/no-quotas/index/%u:CONTROL=/var/no-quotas/control/%u
{{{
mail_plugins = quota
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For IMAP quota you can enable the quota plugin also in 20-imap.conf instead of the global dovecot.conf:
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== Software quotas == {{{
protocol imap {
  mail_plugins = $mail_plugins imap_quota
}
}}}
'''Hint:''' if you get the error message "Can't load plugin imap_quota_plugin: Plugin quota must be loaded also" you've maybe forget to load the global quota plugin as described above.
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Dovecot 1.0 supports quota using a quota plugin. It's currently discussed in [wiki:LDA Dovecot LDA] page and it supports only very simple quota calculation which is suitable only for mboxes. Maildir++ quota support will come later. == Configuration ==
See [[Quota/Configuration]] for backend-independent quota configuration.

== Quota recalculation ==
If your quotas are out of sync, you can use {{{doveadm quota recalc}}} command to recalculate them.

== Quota and Trash mailbox ==
Standard way to expunge messages with IMAP works by:

 1. Marking message with \Deleted flag
 1. Actually expunging the message using EXPUNGE command

Both of these commands can be successfully used while user's quota is full. However many clients use a "move-to-Trash" feature, which works by:

 1. COPY the message to Trash mailbox
 1. Mark the message with \Deleted
 1. Expunge the message from the original mailbox.
 1. (Maybe later expunge the message from Trash when "clean trash" feature is used)

If user is over quota (or just under it), the first COPY command will fail and user may get an unintuitive message about not being able to delete messages because user is over quota. The possible solutions for this are:

 * Disable move-to-trash feature from client
 * You can create a separate quota rule ignoring Trash mailbox's quota. Note that this would allow users to store messages infinitely to the mailbox.
 * You can create a separate quota rule giving Trash mailbox somewhat higher quota limit (but not unlimited).

To make sure users don't start keeping messages permanently in Trash you can use a nightly [[Plugins/Expire|cronjob]] to expunge old messages from Trash mailbox.

Quota

Quota backend specifies the method how Dovecot keeps track of the current quota usage. They don't (usually) specify users' quota limits, that's done by returning extra fields from userdb. There are different quota backends that Dovecot can use:

  • fs: Filesystem quota.

  • dirsize: The simplest and slowest quota backend, but it works quite well with mboxes.

  • dict: Store quota usage in a dictionary (e.g. SQL).

  • maildir: Store quota usage in Maildir++ maildirsize files. This is the most commonly used quota for virtual users.

Enabling quota plugins

There are 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.

Enable them in dovecot.conf:

mail_plugins = $mail_plugins quota
protocol imap {
  mail_plugins = $mail_plugins imap_quota
}

Info: with Dovecot 2.0 you can enable the quota plugin also in 10-mail.conf instead of the global dovecot.conf:

mail_plugins = quota

For IMAP quota you can enable the quota plugin also in 20-imap.conf instead of the global dovecot.conf:

protocol imap {
  mail_plugins = $mail_plugins imap_quota
}

Hint: if you get the error message "Can't load plugin imap_quota_plugin: Plugin quota must be loaded also" you've maybe forget to load the global quota plugin as described above.

Configuration

See Quota/Configuration for backend-independent quota configuration.

Quota recalculation

If your quotas are out of sync, you can use doveadm quota recalc command to recalculate them.

Quota and Trash mailbox

Standard way to expunge messages with IMAP works by:

  1. Marking message with \Deleted flag
  2. Actually expunging the message using EXPUNGE command

Both of these commands can be successfully used while user's quota is full. However many clients use a "move-to-Trash" feature, which works by:

  1. COPY the message to Trash mailbox
  2. Mark the message with \Deleted
  3. Expunge the message from the original mailbox.
  4. (Maybe later expunge the message from Trash when "clean trash" feature is used)

If user is over quota (or just under it), the first COPY command will fail and user may get an unintuitive message about not being able to delete messages because user is over quota. The possible solutions for this are:

  • Disable move-to-trash feature from client
  • You can create a separate quota rule ignoring Trash mailbox's quota. Note that this would allow users to store messages infinitely to the mailbox.
  • You can create a separate quota rule giving Trash mailbox somewhat higher quota limit (but not unlimited).

To make sure users don't start keeping messages permanently in Trash you can use a nightly cronjob to expunge old messages from Trash mailbox.

None: Quota (last edited 2021-06-15 23:54:28 by MichaelSlusarz)