IMAP Implementation People Time Estimates

Marco Colombo marco at
Thu Mar 3 05:51:07 EST 2005

Christopher T. Beers wrote:
> We are in the process of evaluating our current student email solution 
> here at the University and I have been asked to develop some estimates 
> of the time it takes to research, test and implement this.
> The new system must support 35,000 users with about 1500 concurrent 
> connections.  More than likely the setup will have redundant web front 
> ends (2 servers running SquirrelMail, IMP, etc), 1 mupdate server, 2 
> frontend machines and 2 backend Cyrus mail stores.  It will run on top 
> of Linux (RHEL 4 probably).
> We are familiar with UW IMAP server so we have to learn the differences 
> to go to Cyrus, especially the aggregator, backup/recovery, cyradm, 
> etc.  So keep that in mind.
> If anyone has any data that would even remotely be helpful I would 
> greatly appreciate it.  We are comparing Exchange, MiraPoint and this 
> (which is much cheaper) but people now want to compare accurate 
> estimates of people resources to implement it.  To me, that is like 
> asking me how long it would take me to learn [place any abstract task 
> here that you have never done].

Precisely. Learning time depends 20% on how complex the task is and 80%
on how skilled the people involved are. I understand you're having an
hard time extimating the first figure, since you don't know cyrus-imapd,
but how do you expect us to extimate the second one? Not to mention
resources depend also on how long you are planning to test the system,
before you feel comfortable enough to put it in production. Moreover,
I'm sure the cyrus solution offers _a lot_ of different options, and
you may want to evaluate them carefully. Just think of the different
authentication models: are you going to use LDAP? Kerberos? Choosing
the right options is key for a stable system and happy users. Most
commercial softwares do not offer the same amount of options.

       ____/  ____/   /
      /      /       /			Marco Colombo
     ___/  ___  /   /		      Technical Manager
    /          /   /			 ESI s.r.l.
  _____/ _____/  _/		       Colombo at

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