server sizing question

Michael J Barber mbarber at
Mon Dec 29 11:56:05 EST 2003

This is an interesting reply.  It leaves me with more questions than answers.
Then again I am no expert so maybe I am not getting out of this what I should.
A reply in the form of:
System OS:
System Processor(s):
System Memory:
Disk subsystem:
   Drive speed (both bus and spindle)
   Array configuration
   partition configuration and type of filesystem used
IMAP version:
Authentication type (LDAP,SQL, passwd..-same or different machine):
SMTP software/version (same or different machine):
Average connections:
Peak connections:
Load average:
Load average during peaks:
Swap usage during average:
Swap usage during peaks:
Straight IMAP or IMAP with an IMAP proxy in place:
Serve up IMAP and POP or just IMAP:
Primary type of connection: Web-based or client-app (does it matter?)
Then maybe a quick "what if feels like" response, ie. Very responsive for both
web and client apps except during peak usage when waits can be upwards of 15-20
seconds for a web page to load the message listing. 

I know that may sound crazy but we use IMP/HORDE and PMDF IMAP here.  A message
can take over a minute to load!! - That is on the LAN!  We are migrating to
either Cyrus or Courier this spring.... YEAH!

I am not trying to make anybody upset or seem ungrateful for the replies. 
However, scaling issues are a beast if you have no implementation plan or are
looking for someone to suggest an implementation to you.  The number of
variations are infinite.  Soooo, if it is not too much trouble, I would love to
hear about scaling with as much of the above information as reasonably possible.
 I didn't request number of accounts since it is essentially irrelevant, number
of connections are what matters (please correct me if i am wrong).

As a closing note... thanks to all who give feedback, positive or negative. 
Thanks to all those hard working coders who give us a great product.

Michael J Barber
SUNY Plattsburgh
CMS Computer Labs Technician
116D Feinberg Library
Plattsburgh, NY 12901

Quoting Earl R Shannon <ershanno at>:

^^ Hello,
^^ I can't comment on a comparison since I've never heard of
^^ cucipop. What I can do is tell you what we run here at NCSU.
^^ We currently have 4 servers but plan to add 4 more.
^^ The servers are Sun Enterprise 220R's with 2 Gig of memory.
^^ We have over 10,000 accounts per machine. Not all are active
^^ however. They generally have about 1,000 imap processes
^^ running at any given time during the semester with a load
^^ average usually less than 1. Mail delivery spikes sometimes
^^ push the load average up. We have a seperate mail relay
^^ system and use lmtp for delivery to the IMAP servers instead
^^ of postfix or sendmail.
^^ I'm not sure how well you'll be able to map this to an Intel
^^ based server, which I'm guessing you'll be running. But I'd
^^ bet you'd be able to run your proposed load fairly well on
^^ an adequately configured single server, ie, plenty of memory
^^ and speed. And since the servers are very I/O intensive, the
^^ faster the disk subsystem the better.
^^ Regards,
^^ Earl Shannon
^^ Jeff wrote:
^^ > Hi all,
^^ > 
^^ > Does anyone have links to recommended server sizing for cyrus.
^^ > 
^^ > I am migrating away from sendmail/cucipop to postfix/cyrus.  I currently
^^ > have about 7500 mail boxes with about 16GB of mail.  The majority of my
^^ > clients will be popping mail, but we are planning on supporting IMAP now
^^ > that we have good quota support.  Each client will be limited to 20MB of
^^ > storage space.
^^ > 
^^ > How does cyrus compare to cucipop in handling the load.   
^^ > 
^^ > Thanks,
^^ > Jeff
^^ > 
^^ > 

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