General IMAP functionality

[Simon Matter]

> Tarjei Huse wrote:
>
>>tir, 02,.11.2004 kl. 11.39 -0500, skrev Warrick FitzGerald:
>>
>>
>>>Earl R Shannon wrote:
>>>
>>>
>>>
>>>>Hello,
>>>>
>>>>Comments are imbedded below.
>>>>
>>>>Warrick FitzGerald wrote:
>>>>
>>>>
>>>>
>>>>>Posted this last night, but did not see it come through ... sorry
>>>>>about the re-post if you have this already.
>>>>>
>>>>>
>>>>>===========>>>>
>>>>>Iÿm in the process of moving an office of POP3 users to IMAP, and
>>>>>realized that that I donÿt fully understand how things normally work.
>>>>>
>>>>>Our mail is currently hosted on an ASP basis and when a user is
>>>>>running out of disk space they receive an email saying youÿre running
>>>>>out of space. I tested what happens on the IMAP side, and using
>>>>>Mozilla Thunderbird I get a message popup saying pretty much the same
>>>>>thing, but I only get this once Iÿve run out of space.
>>>>>
>>>>>  1. Can I set Cyrus to prompt when the usersÿ mailbox reaches 90%
>>>>>usage?
>>>>>
>>>>>
>>>>    Yes. The server sends what the IMAP protocol calls an ALERT. The
>>>>client is responsible for handling it accordingly. This usually means
>>>>a POPUP. You'll need to look through the imapd.conf man page to see
>>>>how its set.
>>>>
>>>>
>>>>
>>>>>  2. Is it possible to email an admin account when this happens? Many
>>>>>     users donÿt understand how to free space on the server and need
>>>>>     assistance (save the comments please J ).
>>>>>
>>>>>
>>>>     No, Not with the native software. We've written a script that
>>>>will go through and send a message to the user letting them know that
>>>>they are filling up and generate a list of those people which then gets
>>>>sent to the admins.
>>>>
>>>>
>>>>
>>>>>Now hereÿs the part I donÿt fully understand. As far as I can gather
>>>>>youÿre responsible for moving mail off the server onto you local
>>>>>machine on some regular interval. Outlook seems to have this
>>>>>´Archiving feature¡ thatÿs responsible for this, but Iÿm not sure if
>>>>>this is the Microsoft way of doing things, or the right way of doing
>>>>>things.
>>>>>
>>>>>
>>>>    Yes, the user is responsible. The IMAP protocol makes not effort
>>>>to make this happen. Any ARCHIVE feature such as you mention is a
>>>>function of the client software.
>>>>
>>>>
>>>>
>>>>
>>>>>I donÿt seem to find an ´Archive¡ feature in Thunderbird. What am I
>>>>>missing here?
>>>>>
>>>>>
>>>>    See above. The whole point of IMAP is to store the messages
>>>>on the server. Keeping below an adminstratively imposed quota is the
>>>>users responsibility. Sadly, not all users are responsible. :)
>>>>
>>>>
>>>>
>>>>>Thanks
>>>>>Warrick
>>>>>
>>>>>---
>>>>>Cyrus Home Page: http://asg.web.cmu.edu/cyrus
>>>>>Cyrus Wiki/FAQ: http://cyruswiki.andrew.cmu.edu
>>>>>List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html
>>>>>
>>>>>
>>>>Another space issue that new IMAP users sometimes have difficulty with
>>>>is the Trash model of deleting stuff. This is a client configurable
>>>>thing so some people see it, others may not. But they move a message
>>>>to Trash when they delete and don't empty the Trash. It will still use
>>>>their quota.  And if they keep copies of sent messages on the Server,
>>>>same deal. They use quota.
>>>>
>>>>Have fun.
>>>>
>>>>Regards,
>>>>Earl Shannon
>>>>
>>>>
>>>Thanks Earl,
>>>
>>>That's what I was afraid of. Sounds to me like the people who aren't
>>>going to "get" this concept should keep using POP3 :)
>>>
>>>
>>
>>Or embrace the concept of IMAP =)
>>
>>The fact that you do not loose your mail when your disk gets lost is a
>>very good reason to use IMAP - that is if you backup your server. Also,
>>you can provide offsite access to mails via webmail and / or imap as
>>well as provide your users with shared folders (something mine loved).
>>
>>
>>
>>>1. Does anyone have "best practices" that I can share with users on how
>>>they should move mail off the server when their quota is exceeded?
>>>
>>>
>>I'd rather buy a bigger harddrive! How many users do you have? 50, 100,
>> 10 000?
>>
>>
>>
>>>2. What is considered a reasonable quota (I know this is a very broad
>>>question)? When working with POP3 I would allocate users a max of 50 MB,
>>>when does a mailbox have so many messages that it puts a burden on the
>>>server?
>>>
>>>
>>My users have a quota of 2 gb (2x gmail) on one site and 100 mb on
>> another (with a select few having a quota of 500 mb).
>>
>>Cyrus does not have a problem with this. Reasonable quotas is something
>>that IMHO is a function of your budget. It is better to keep users mail
>>on the server that have them keep the mail localy.
>>
>>
>>Tarjei
>>
>>
>>
>>>Thanks
>>>Warrick
>>>
>>>
>>>
>>>
>>>---
>>>Cyrus Home Page: http://asg.web.cmu.edu/cyrus
>>>Cyrus Wiki/FAQ: http://cyruswiki.andrew.cmu.edu
>>>List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html
>>>
>>>
> Great thanks that gives me a lot more confidence. I'd tested a while
> back using UW Imap and have a very bad experience. I didn't have maildir
> config setup and was reading 1GB of mail from one huge mail file and it
> took about 20 minutes to connect every time I needed to do something. I
> also could not port any of my mail and ended up trashing the lot.
>
> If Cyrus can handle mailboxes of this size, that is certainly the
> aproach I'll take. I dont have many users that will be using IMAP so
> space should not be a huge problem.

Cyrus handles large mailboxes very nice. We have quotas of 1G per default
and up to 4G on several servers and it really doesn't seem to affect
performance too much. Of course some operations may slow down if you have
1G in one folder, but most people don't do that :)

Simon


---
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