[Dovecot] Dovecot shared quota with Maildir

[Jorgen Lundman]

> 
> With v1.2 this would be somewhat easier I think, because it allows you
> to create new user structures, look up their home dirs (by querying
> dovecot-auth) and calculate their quotas. But you'd still need a way to
> get a list of usernames who share the quota.
> 
> All of this is actually related to "domain quotas" that I've been
> thinking about for a long time. If there was a way to recalculate the
> quota for multiple users I'd be interested in getting the code added to
> Dovecot.

"domain quotas" is a good way to describe it.

It would need some method to look up all mail-storage that is belong to 
the domain. In our case, we would look at an LDAP query, where uid=uid 
and gid=gid, but could be a literal search as well. (o=$domain, ...). 
Since the uids are the same (it is how you do shared quota with fs-quota 
after all), we do not have any uid/chown/chmod issues.

More generically, there needs to be some way to get the list of 
connected accounts, from any backends, not just LDAP. And the data 
relationship should be configurable.

After that, the recalculation would need to iterate said list. I 
presumed that Dovecot already had logic to deal with multiple accounts, 
since the wiki lead me to believe one could do shared quotas with 
symlinks. [1]

We would need this feature in the next 2 weeks, so I will most likely 
break-down and hack it in, but naturally it would be much better if it 
was done Officially for ease of future upgrades (and probably more 
reliable).


[1] Speaking of symlink-shared-quotas. If I create say 2 domain 
accounts, both which symlink to each other, I would guess it ends up in 
an infinite loop, or is it clever enough to break after depth of 1 symlink?





> 
> On Tue, 2009-03-10 at 11:59 +0900, Jorgen Lundman wrote:
>> Since I could issue an LDAP query for 
>> (&(uidNumber=%uid)(gidNumber=%gid)) for homeDirectory to retrieve all 
>> home directory paths, and associated mailDirSize files, I wonder if I 
>> could extend dovecot to allow us to handle shared quota like the 
>> fs-quota used to work.
>>
>> Using symlinks between accounts would very quickly deteriorate.
>>
>> Lund
>>
>>
>>
>>
>> Jorgen Lundman wrote:
>>> Hello list,
>>>
>>> We are in the process of exploring the idea of moving from UFS with 
>>> fs-quota to using softquotas in Dovecot (probably Maildir type, stored 
>>> in LDAP, all ontop of NFS).
>>>
>>> I have it setup, and it works rather well so far.
>>>
>>> But there is one situation we can currently support, which I can not see 
>>> a solution for with soft-quotas.
>>>
>>> Generally customers get 1 email, with 1 quota.
>>>
>>> But it is also possible for customers to get 1 quota, but create 
>>> multiple mail accounts, all sharing the same quota. This is done by 
>>> using the same UID for each account when using fs-quota.
>>>
>>> (It is not that each account gets a fraction of the quota, but that all 
>>> accounts add up to the one quota).
>>>
>>> Is this still possible to do with soft-quotas. To share one set. Dovecot 
>>> would have to go count files in multiple mail-directories so I would 
>>> guess no.
>>>
>>> Lund
>>>

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