[Dovecot] Dovecot performance under high load (vs. Courier)

[Brian Hayden]

On Jun 21, 2012, at 3:22 PM, Timo Sirainen wrote:

> On Thu, 2012-06-21 at 13:05 -0700, email builder wrote:
>> Thank you very much for the fast reply.
>> 
>>>> We are building a new system that will support a large number of users 
>> 
>>>> (high volume, high concurrent usage, etc).  We have played with Dovecot, but in 
>>>> most serious applications we have traditionally used Courier IMAP.  It's my 
>>>> (lay) understanding that with indexing and perhaps other things in Dovecot, it 
>>>> might perform better than Courier in larger environments like this.  Am I 
>>>> correct or is it less clear-cut?
>>> 
>>> If you disable index index files in Dovecot, its performance should be slightly 
>>> better than Courier. With index files the performance is typically much better 
>>> in Dovecot, especially if you use a (non-caching) webmail.
>> 
>> Interesting.  What would be the motivations for disabling indexing?
>> Indexing is by default enabled?
> 
> Yes, enabled by default. There aren't many good reasons for disabling
> indexing.
> 
>> Do you know what webmails are caching vs. non-caching?  
> 
> Nearly all of them are non-caching. (I don't know of any caching ones.)

Prayer, from University of Cambridge, or Chickadee, a fork of it. It's essentially a proper IMAP client in C that runs on a server, and uses HTTPS (via an embedded server, no external dependency on apache or etc.) to the end user just to deliver the display. 

When I was on the email project for the University of Minnesota, I modified it heavily for interface and to add some features that admins are used to having in systems where apache is involved (virtual hosts, things like that). I have it available (GPL) as a vanilla, de-branded package--Chickadee. Website is currently offline as I've been switching hosts, anyone who's interested can feel free to drop me a line.

-Brian