Re: [Exim] MTA-imposed quota exceeded

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Author: sys044
Date:  
To: ph10, sys044
CC: exim-users
Subject: Re: [Exim] MTA-imposed quota exceeded
The issue, as I see it, is whether EXIM quota is a filespace quota
or a user mail INBOX quota. The first protects the system filespace
whereas the latter protects the user INBOX and helps manage the system
filespace.

From the few replies I have had on quotas, not many use the EXIM
quotas as an INBOX management system but primarily as a hard limit
to avoid system full. Some apply other methods as well (mailclean -
as we used to use).

We have been using EXIM quotas for just a short time for user INBOX
management and have run up against many practical problems of
users going over quota. This includes the classical problem of how
do you inform a user who is over quota that an important large
message is waiting.

In the EXIM system, with a moderate quota, it is possible for a
user to continue to receive small messages while a large message is in
the spool, unknown to the user. The user may appreciate they are near
the limit as they have had a threshold warning but as they still receive
mail they are not aware of the messages which are delayed and may be
rejected. This is inconsitent - or will result in the user saying
"why did you not tell me it was waiting".

In the system I proposed as a configurable alternative, all message
are delivered until the INBOX is over quota and then an over-quota
message generated. This clearly requires a category of messages that
can be delivered even if over-quota. The threshold message continues
to be generated and is always delivered.

This scheme tells the user the information they need when they
look at their mail and it is clear that NO message will be delivered
to them regardless of size until they make some space.

The advantages of this scheme for me is

   a. it informs the user when over quota and the user is the one
      who needs to know and take action not the originator of the
      delayed message. Good USER information.


   b. mail is never spooled or rejected for a user while other smaller
      messages are delivered. A consistent delivery scheme.


The current scheme is too USER unfriendly - our user services are not
happy with it at all. Perhaps it is the newness of the scheme but ....

I hope I have made the issues clear enough. I have now made my point, again,
and for the last time to the list.

John Linn (j.linn@???)