Large cyrus install surver

Earl R Shannon ershanno at
Wed Dec 3 10:51:52 EST 2003


Information provided below.

Earl Shannon

sjh at wrote:
> Hi,
> I'm looking at setting up IMAP servers for a mid-sized (2,000-3,000)
> company with several sites around the world.  I've run Cyrus myself
> for years, and I'm very happy with it.   But, I'd like to collect some
> configurations from people with large scale installations (CMU does
> not count :).
> If people will email me their info, I'll make a little web page, and
> post the results here so that others can benefit as well.
> Send me:
> The version(s) of Cyrus you are running

> The specs of the servers you have (cpu,mem,disk,os, etc)
4 Servers:

Sun Enterprise 220 R with one CPU

2 Gigabyte of RAM

We are using a Fiber Channel SAN architecture with two Sun T3's.
The SAN currently provides each IMAP server with 100GB of space.

Currently Solaris 7

Adding 4 more.

Sun Enterprise 280 R with one CPU

2 Gigabyte of RAM.

> How many accounts on each server.

Average is 15102. Total accounts 6040. It should be noted that
not all of these are active. Students are a transitory lot to say
the least.

We allot all users 30 MB initially. Additional quota may be

Authentication methods are GSSAPI, KERBEROS_V4 TLS+PLAIN PLAIN
The PLAIN methods use saslauthd, wich is using the kerberos4
mechanism. Sadly, we still have a memory leak using kerberos5,
and the -n 0 flag actually slows down authentication too much
due to the forking overhead. ( No pun intended :) )

> The average and peak number of users on each server at a time

Average is between 700 and 1000 depending upon the server. We haven't
yet been able to identify users based upon a usage pattern and who
they are to effectively load balance among the servers yet.

Peaks as high as 1400.

Loads usually stay below 1.

We have limited the number of lmtp processes allowed to run to 50.
Occassionally we get flooded with email and the delivery process
will causing user problems. We decided it was better to slow dowm
mail delivery as opposed to users not being able to login.

> The average and peak number of messages in a folder for your users
>  (go ahead and estimate here...)

Big guesses. A lot of people don't keep any on the server.
Others have over 1000. A few have over 100 folders.
They haven't yet grasped the concept ofcopying to a CD if they need to 
keep it. A user education issue we need to address along with making 
archiving easier.

> Are you using murder?  If so, describe your proxies and mupdate server.

Not Yet. Want to. Will make our shared mailbox server integrate much nicer.

> Any random thoughts you have.  Would you pick Cyrus if you were free
> to start over right now? etc.

I did not do the initial IMAP server evaluation. But from what I learned
since I would stick with it. We will be adding another four servers and
increasing the available space in the SAN. We will then redistribute our
users over 8 instead of 4, and increase the default user quota to 50MB. 
As I already indicated we very much want to get the murder implemented. 
While it doesn't provide the high availability it will make other things 
easier for our support staff and users, particularly our webmail ( we 
use SquirrelMail ) users.

> What info about you (firstname, lastname, email, organization) is it ok
> for me to list with your info. (none at all is fine, and that's what I'll
> assume if you don't say otherwise)

Earl Shannon
Earl_Shannon at
North Carolina State University, Information Technology Division

> email your info to sjh at
> Thanks,
> -Seth

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