Experiences with Mail servers

[Jason Dixon]

On Dec 5, 2004, at 10:21 AM, Chris Mason wrote:

>> There is no reason why the average colocated server (dual Xeon 
>> exceeds my
>> definition of such) shouldn't be able to handle that load.
>
> We have our own datacenter.

I was emphasizing that your existing server should be sufficient for 
your load requirements.

>> What kind of testing have you done?  What size are you "large mail
>> folders"?
> One user has 4GB of data, each folder can be 30-100 MB.

What kind of testing have you done?  I would suggest formulating a test 
plan and then execute on it.  First, create a duplicate server for 
testing.  Except for the test changes, everything else should be equal. 
  Next, I would convert a handful of your user accounts (on the test 
server) to maildir (http://batleth.sapienti-sat.org/projects/mb2md/), 
and run performance comparisions between the two.  Some test scripts 
running fetchmail should suffice for real numbers.  Then make both 
servers available to the handful of test servers for "anecdotal" 
experiences.

If maildir looks like a good solution for you, don't stop there.  Test 
your hardware.  How is the disk performing under load?  Would your 
arrays (if any) be better suited to a different RAID configuration (if 
any)?  Come on, test that server!  :)

Mind you, this only addresses the retrieval aspect of the mail 
experience.  You haven't suggested anything to suspect any problems 
with mail delivery (SMTP), so I have to assume you're only referring to 
delays in mail viewing, retrieval, etc.

>> We've started looking at Open-Xchange
>> (http://mirror.open-xchange.org/ox/EN/community/) for groupware
>> solutions.  The demo is very impressive, and the price can't be beat.
>
> How difficult is the migration? I can't ask them to start all over 
> again.

We haven't migrated anyone, so I can't tell you.  If you can't "ask 
them to start all over again", then why bother looking at alternatives 
anyway?  ;-)

--
Jason Dixon
DixonGroup Consulting
http://www.dixongroup.net