[mdlug] Quotas. How do they work?

[Robert Adkins II]

Thank you Mark.

I did actually install a new HD into the server and made it the new /home
directory.

The reason for holding these users to a quota is important. If I do not,
then they will continue to grow their email storage, indefinitely. It is
literally a teeth pulling operation to "permanently" remove data from the
servers that is 6 years out of date. So, I'm looking at having to manage
inboxes with a potential size of "unlimited".

Thanks,
Rob

 

> -----Original Message-----
> From: Mark Montague [mailto:markmont at umich.edu] 
> Sent: Tuesday, March 29, 2011 10:42 AM
> To: mdlug at mdlug.org; radkins at impelind.com
> Subject: Re: [mdlug] Quotas. How do they work?
> 
>   On March 29, 2011 10:16 , "Robert Adkins II" 
> <radkins at impelind.com> wrote:
> > I am seeking to force certain users into trimming back the size of 
> > their email stored on the IMAP server. Much of the data 
> itself doesn't 
> > need to be stored in email long term, as it is replicated 
> elsewhere on the network.
> >
> > The problem is, if I just toss in a quota I am concerned that there 
> > will be no warning, just suddenly they will be unable to 
> send/receive 
> > email. Nothing I am seeing the in the tools for enabling quotas 
> > suggests that the users will receive any form of warning.
> >
> > Is this true?
> 
> Are you sure you want to impose quotas?  At the University of 
> Michigan (for example), adding another drive to an IMAP 
> server's RAID array (or upgrading the drives to higher 
> capacity ones, if possible) is cheaper than imposing and 
> managing quotas, and then paying for the resulting end user 
> support.  Plenty of people have 5 GB, 10 GB, even 20 GB 
> mailboxes, and the very rare problem cases can usually be 
> addressed by having a chat with the offending user.  (If this 
> sounds radical, keep in mind that as of today, Google is 
> providing 7.6 GB per user at no cost, with extra space 
> available very cheaply).
> 
> Alternatively, have a script that runs daily that sends 
> annoying nags to people who are using more space than you 
> would like.  "You have more than 10 GB of email on the 
> server; please be a good citizen and free up some space.  
> Call 555-1234 if you'd like assistance with downloading 
> some of it to your desktop, or otherwise archiving it."    
> You may also 
> want this script to look for and notify the user about common problems
> -- such as a Trash or Junk Mail folder that has lots of 
> things in it (hundreds of megabytes).
> 
> But, assuming you really do want to use quotas:
> 
> - Use IMAP quotas rather than Unix filesystem quotas, if at 
> all possible.  This will give you much more "intelligence", 
> nicer failure modes, and hopefully better control.
> 
> - Configure your SMTP / LMTP server to hold messages for up 
> to 7 days if they cannot be delivered due to a mailbox being 
> over quota.  Only bounce (or discard) the message after that 
> time, if the user has not freed up space in their quota.  
> Test this regularly to be sure that messages only get 
> delayed, not lost, if a user goes over quota but then frees 
> up space within a week.
> 
> - Provide a web interface where people can check their 
> current quota usage.
> 
> - Keep in mind that if the user uses a client that uses a 
> Trash folder, this can sometimes complicate things.  See the 
> question "Why can't I delete any messages from my over-quota 
> mailbox?" at http://www.cyrusimap.org/docs/cyrus-imapd/2.4.6/faq.php
> 
> - Run a script such as the one described above that warns 
> people when they get close to their quota so that they are 
> not surprised.
> 
> 
> I hope this helps.
> 
> --
>    Mark Montague
>    mark at catseye.org
> 
> 
> 
> 
> --
>    Mark Montague
>    mark at catseye.org
>