[Dovecot] Quota and Trash

[Robert Schetterer]

Hi Bernhard,

Bernhard Schmidt schrieb:
> On Mon, Mar 12, 2007 at 06:01:05PM +0100, Robert Schetterer wrote:
> 
> Hi Robert,
> 
>>> Currently they use maildir++ quota format. Mails moved to Trash get not
>>> included in the Quota calculation (standard "feature" of Courier IMAP)
>>> and get expunged after a certain period of days (IMAP_EMPTYTRASH).
>> use ignore trash parameter, this should do the job, read the wiki
> 
> It does a similar job, I've read the wiki very thoroughly, but it does
> not do the same, at least according to the documentation

jep your right its not the same to courier, but is see no real problem
if using ignore trash and trash plugin together you have a function wich
solves the problem too, ok mail in trash get added to your quota, but
users would not get into trouble with that, and its not of evil if they
mean they got less quota left, it would only be a problem if they mean
they still have place to store

> 
> Courier ignores Trash for Quota calculation, means that when I move a
> mail from "INBOX" to "Trash" my used quota is decreased.
> 
> Dovecot does not ignore the Trash for Quota calculations. When I move
> (delete) mail the quota is decreased (delete from INBOX), then increased
> by the same value (append to Trash). The ignore option only allows
> Dovecot to ignore quota _violations_ when appending to Trash.
> 
>>> This issue is directly related with the second one. Deleting old mails
>>> in Trash could be archieved with the expire-plugin, but that does not
>>> work with Dovecot v1.0, and I'd definitely want to run this. So I have
>>> to use "find", which deletes the mail from the folder. However, those
>>> mails are still included in the Quota calculation, so that will very
>>> likely become incorrect.
>> perhaps you might try trash plugin, which deletes mail i.e trash
>> folder if the the mailbox would run over quota by incomming mail
>> this seems to me a better koncept, than simply delete mail by their age
>> read the wiki about it.
> 
> It is not the same. The mailservers and the storage would explode
> horribly if all ~15k users would be able to keep their Trash filled
> until they reach their Quota. Allowing them to reclaim accidentally
> deleted mails from Trash for three days has proven to be a good solution
> here.

youre right, but the koncept of deleting mails from i.e trash as long as
place can be made free doesnt brake the whole mailbox quota, cause if
there isnt any mail left to delete ( after all the oldest ones got
deleted first ), the incomming mail will be bounced with overquota
message, youre right this maby result in miracle questions by your
users, but this is only a question how to give that faq to them.
> 
>> cant say what you mean by quota calculation, i use quota in mysql , so i
>> have realtime quotas with thunderbird imap
> 
> Well, I guess you have the same issue then.

no i see no problem, works as designed
> 
> As explained above, when I move a message to Trash in Dovecot it is
> still counted on the used space in the quota calculations, thus included
> in the maildirsize. When I remove mails manually now on the filesystem
> (e.g. using the "find .  -mtime ..." listed in the wiki), they get
> removed from the storage, but since find does not touch maildirsize they
> are still counted in there. So after some iterations the quota in
> maildirsize would be used to 100%, while the user would only be using a
> fraction of it on the disc.

if you using a script simply rewrite maildirsize too if needed.
i use postfix vda , and it does the rewrite if  new quota is set
in sql with the next incomming mail, dovecot never had a problem with
that, after all you will see the new quota in imap after next restart of
thunderbird, this issue must be given to users as server faq, and its
the same with using maildrop and touching maildirsize out of sql
> 
> I think the problem appears whenever you use tools on the maildir
> backend that do not handle quota. Whether the value is stored in
> maildir++ or dict should not make any difference, as long as the value
> is stored somewhere. Quota backends like fs or dirsize don't suffer from
> this, but fs is not usable in our environment and dirsize has a heavy
> performance penalty.
> 
> So having a solution for my first problem (ignoring Trash in Quota
> calculations, _not_ violation processing) would solve the second, since
> mails deleted (or not deleted) there are not in quota anymore.
> 
> Regards,
> Bernhard
> 
i have servers with cyrus, courier and dovecot in production
and i have no problems with them and none of our users have,
choose the one which fits best to your needs.

-- 
Mit freundlichen Gruessen
Best Regards

Robert Schetterer

https://www.schetterer.org
Munich/Bavaria/Germany