Question about cyrus quotas - how it behaves
David R Bosso
dbosso at lsit.ucsb.edu
Wed May 4 18:58:18 EDT 2005
--On May 4, 2005 4:19:51 PM -0600 Sun Advocate Webmaster
<webmaster at sunad.com> wrote:
> Just a question for all of you about quotas on cyrus imap.
> As far as I see, there is no "grace" quota or warning system. Users not
> watching the size of their mailboxes won't know they're near full until
> they're actually full. Is this the case?
Check out quotawarn: and quotawarnkb: in man imapd.conf. They result in
IMAP ALERT messages being generated.
> Lets say a user has a 20 MB quota on their mailbox. Lets say it currently
> sits at 19 MB (usage). Then, assume postfix hands over a 1.5 MB email
> (uncommon, but if there are attachments...). Does Cyrus accept this
> message but no further emails, or does it flat-out deny it?
The former. Mail isn't rejected until the box is over quota.
> If it does deny this 1.5 MB email, does it accept a 3k email from postfix
> that arrives moments later?
> I assume once the quota has been exceeded, users won't be able to receive
> new email until they delete old ones. Is the quota restriction/ban
> "lifted" immediately after the offending user deletes enough of their
Yep. It's also a non-fatal delivery failure, at least on my setup. So
mail will continue to be retried until a hard fail, 5 days or so.
> Most of my IMAP users (local subnet) will be using Mozilla Thunderbird.
> The remaining users will be mostly POP on Outlook (remote users).
POP is a problem because it doesn't provide any feedback like IMAP ALERT.
In addition to the IMAP ALERTs provided by the quotawarn settings, we do a
weekly cron script that sends an email to users approaching quota.
David R Bosso <dbosso at lsit.ucsb.edu>
Systems & Network Manager, Letters and Science IT
UC Santa Barbara - 1054 North Hall 805 451-7160
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