[cyrus 3.0] 20 delayed mailbox deleted limit?
morgan at orst.edu
Thu Jun 9 12:27:59 EDT 2016
On Thu, 9 Jun 2016, Andre Felipe Machado via Info-cyrus wrote:
> Bron Gondwana via Info-cyrus <info-cyrus at lists.andrew.cmu.edu> wrote ..
>> On Thu, Jun 9, 2016, at 03:02, Andre Felipe Machado via Info-cyrus wrote:
>>> At future release notes I read
>>> "Under delete_mode: delayed, only the 20 most recently deleted mailboxes are
>> kept for any given name."
>>> Is there any configuration parameter to increase this limit?
>>> Why this limit is needed?
>> denial of service / space wastage protection. There's no config option available
>> right now. I could be convinced to change it.
>> How would you suggest we protect against exploiting delayed delete to fill the
>> server without going over quota? Maybe a new quota field for "total mailbox usage
>> including deleted stuff" that can be set to a high enough value that no reasonable
>> user will ever hit it?
>> Bron Gondwana
>> brong at fastmail.fm
> Hello, Bron
> I understand the problem.
> But at a corporate scenario, it is a rare event, because of jobs at stake, tracked user accounts, antispam measures, etc.
> It is more likely a "rogue" client, bug/misconfiguration on a smartphone causing such problems.
> We stay with official debian repositories versions as long as we could, receiving security patches.
> So, mantaining an unofficial patch will be a big problem.
> The sysadmin configurable parameters will be a more elegant solution.
> Having configurations at sysadmin control will mantain cyrus flexible for use at different usage scenarios.
> For the DoS / waste space problems, the 2 quota limits configurations are more suitable than counting folders quantity.
> What if each folder contains 1 TB deleted messages?
> Maybe a reasonable default (10 times user quota?) for those not wanting to configure is good idea.
> Even better to have also a way to control individual accounts total quotas, for those corporate accounts like "sales at foo.bar" that receive lots of legitimate emails and have to
> delete them after processing.
> We have zabbix monitoring space at our cyrus backends, and need unlimited or configurable delayed expunge limits for recovering messages and folders for years at corporate
> Thanks .
> Andre Felipe
Remember, this is a limit on the number of deleted *mailboxes* kept, not
Bron, this could impact Pine/Alpine users that frequently postpone
messages. Pine creates a folder named "postponed-msgs" to store drafts.
The folder is created when a draft is saved and deleted when all drafts
have been deleted/sent.
Here is my personal deleted folders list, right now:
DELETED.user.morgan.postponed-msgs.5755CF0C 0 p2 morgan lrswipkxtecda
DELETED.user.morgan.postponed-msgs.5755F446 0 p2 morgan lrswipkxtecda
DELETED.user.morgan.postponed-msgs.5755F486 0 p2 morgan lrswipkxtecda
DELETED.user.morgan.postponed-msgs.5755F4D1 0 p2 morgan lrswipkxtecda
DELETED.user.morgan.postponed-msgs.5755F4E4 0 p2 morgan lrswipkxtecda
DELETED.user.morgan.postponed-msgs.5755F50E 0 p2 morgan lrswipkxtecda
DELETED.user.morgan.postponed-msgs.5755F65F 0 p2 morgan lrswipkxtecda
DELETED.user.morgan.postponed-msgs.5755F844 0 p2 morgan lrswipkxtecda
DELETED.user.morgan.postponed-msgs.5756ECFC 0 p2 morgan lrswipkxtecda
DELETED.user.morgan.postponed-msgs.5756F602 0 p2 morgan lrswipkxtecda
DELETED.user.morgan.postponed-msgs.575706F8 0 p2 morgan lrswipkxtecda
DELETED.user.morgan.postponed-msgs.57585C5D 0 p2 morgan lrswipkxtecda
DELETED.user.morgan.postponed-msgs.57587FE1 0 p2 morgan lrswipkxtecda
We are removing deleted mailboxes after 7 days:
delprune cmd="/usr/local/cyrus/bin/cyr_expire -E 1 -X 7 -D 7" at=0100
I don't know if other IMAP clients have similar quirky behavior, but I
could see myself running into this limit. However, I certainly don't care
about recovering my old postponed-msgs mailboxes.
Hmmm, is this a limit per-mailbox (user.morgan.postponed-msgs) or per-user
(all mailboxes under user.morgan)?
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