Fwd: Re: Does anyone allow unlimited or extremely large quotas?

[David Lang]

On Tue, 16 Nov 2010, Dave McMurtrie wrote:

> I didn't realize that I only responded to Rob here.  Perhaps my
> additional information will shed some light on the kind of information
> I'm looking for.
>
> -------- Original Message --------
> Subject: Re: Does anyone allow unlimited or extremely large quotas?
> Date: Tue, 16 Nov 2010 07:06:53 -0500
> From: Dave McMurtrie <dave64 at andrew.cmu.edu>
> To: Rob Mueller <robm at fastmail.fm>
>
> On 11/16/2010 06:45 AM, Rob Mueller wrote:
>>
>>> This may be slightly off-topic, so apologies in advance. Is there
>>> anyone out there who allows unlimited quota for their users or provides
>>> extremely large quotas when asked for?
>>
>> What do you consider extremely large? And what sort of problems are you
>> referring to?
>
> I don't actually know what sort of problems I'm referring to, hence the
> question.  The big problem I can imagine would be opendir() and
> readdir() with a huge number of files in a directory, but the cyrus code
> doesn't appear to do that in a lot of places that would matter to a user
> (deleting an entire folder, delete sieve scripts, etc) in the course of
> normal operations.

this depends on what filesystem you are useing, I have mailboxes with hundreds 
of thousands of messages in them on XFS and have no problems, but on ext3 I 
start seeing slowdowns with a bit over ten thousand messages.

>> The usual issue is just the huge number of emails and thus files that
>> accumulate. Creating a fresh replica, body searching, reconstructing,
>> etc all take quite a bit of time because of the large amount of random
>> IOs. Apart from that, everything does actually work ok...
>
> The only issue we ever had was with a bboard that our network group
> sends automated system messages to.  Something in their environment went
> haywire and we ended up with ~1.5 million messages in that bboard.  They
> were unable to find a client that was willing to deal with the folder to
> be able to clean it up.  I was able to connect using imtest and SELECT
> and FETCH messages without any problems, though.  I also recall that
> replication was broken by this folder, but I don't remember exactly why.

alpine and mulberry have no problem with huge numbers of messages.

David Lang