Cyrus IMAP ; case studies, success stories, ... I need them

[Paul M Fleming]

We've been using Cyrus IMAP since 1998 version 1.5.19. We just recently
upgraded to 2.1.11 and couldn't be happier. We do have several folks who
use Outlook as an IMAP client for email and the Exchange native
calendar/groupware features. I'm told integration does suffer slightly
in this setup -- institutionally we use Steltor/Oracle CorporateTime for
calendaring. 

We support 3000 users using a cluster of 4 backend machines and 3 front
end machines. (frontends are load balanced crudely via Round Robin DNS,
the backends are balanced by where we create mailboxes) Concurrent
logins hover at 350-450 - we have spiked to 10 logins/second without
problems. We adopted the clustering setup for performance and
availability reasons and are VERY glad we did it this way. We can
increase our capacity without downtime or user notification -- we've
done it several times.  Our system uses Kerberos as the backend
authentication system. We use LDAP to route mail within the cluster --
via sendmail ldap routing. Cyrus is an excellent performer -- but I
would encourage you to do some testing before deploying a large
installation. Our pre deployment testing (using
http://www.etestinglabs.com/benchmarks/svrtools/email/t1intro.asp?visitor=X)
helped us tune our IO subsystems for better performance (use Hardware
RAID). It also uncovered some additional performance issues: We found: 

	IO IO IO -- Cyrus is all about IO. Pay alot of attention here. At least
on PC class gear hardware RAID w/ cache is almost a requirement in any
decent size install. We used software raid for 3 years -- 3 painful
years.
	LMTP seems to work best with a limit of 10 processes due to BDB locking
on the deliverdb.

Our internet based inbound delivery is handled by 4 different machines
doing LDAP routing, mimedefang and spamassassin. Our internal inbound
SMTP handling is handled by the imap front-ends. We have just started
using Sieve but it appears to work great. Our webmail interface (IMP) is
on yet another machine.

The backend servers
	Base Box is
http://www.supermicro.com/PRODUCT/SUPERServer/SuperServer6021H.htm
	PIII 1Ghz
	1GB RAM
	Mylex 352 RAID w/ BBM and 32Mb
	4 - 37Gb U160 Seagate Drives

The front-end machines: (currently run custom proxy code -- switching to
CMU murder soon)
	PIII 1Gz
	512Mb RAM
	Single 18Gb U160 Drive

You can read my original (OLD) paper on our cluster at (predates CMU
murder I think)
http://www.siumed.edu/~pfleming/development/email/

One of these days I'll get the current setup documented. 

Paul Fleming
SIU School of Medicine
Springfield IL



Piet Ruyssinck wrote:
> 
> Hi all,
> 
> I have set up a test machine with cyrus imapd 2.1.11 and everything
> that goes with it.  Very nice system, working perfectly, in a test
> environment of some 30 people.
> 
> Today, I went to see management, to get money for the production system
> hardware (I'm thinking about a full Sun Fire 280R with a full Sun
> StorEdge 3310 SCSI Array),
> ... only to hear that some other people are working on a solution based on MS
> Exchange, because they want the groupware functionality.
> 
> I might be able to convince them to adopt Cyrus imapd, if only I can
> assure them that it will peacefully coexist with MS exchange.  They can
> agree on using Cyrus for e-mail, and Exchange for the groupware stuff.
> But, being a full time unix admin, I have no clue about exchange.  Is
> such a setup possible ?  Or does Exchange rely on its own e-mail system ?
> 
> Together with information, I could also use any Cyrus imapd success
> stories that I can get.
> 
> If you're running Cyrus for a reasonably sized company or institution,
> please let me know, including the hardware you're using, number of
> (simultaneous) users, level of satisfaction, and other useful
> information.  Maybe we could collect this data in some kind of
> registry.
> 
> Looking forward to your replies,
> Piet Ruyssinck
> 
> -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
> Piet RUYSSINCK                            e-mail: Piet.Ruyssinck at rug.ac.be
> Unix Systeem Administratie                             tel: +32 9 264 4733
> Directie Informatie- en Communicatietechnologie (ICT)  fax: +32 9 264 4994
> Universiteit Gent (RUG)      Krijgslaan 281, gebouw S9 - 9000 Gent, Belgie
> -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
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