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Re: standalone imap servers



Quoting Matthew Weigel (Matthew_Weigel_(_at_)_t-pyxidis_(_dot_)_fac_(_dot_)_cs_(_dot_)_cmu_(_dot_)_edu):
> > >Cyrus is just lovely. You deliver to it, you use IMAP to get
> > >from it.  No unix users - just mail users.  How more
> > >standalone is there?
> > 
> > I agree. I am more in favor of courier. Believe it or not,
> > maildir via imap is blazingly faster than with /var/spool mbox
> > type of delivery.
> 
> Ummm.  This is relevant to *what* when talking about Cyrus?  Try
> scanning a 10,000 message mailbox when you *don't* have to do
> 10,000 stat()s.

And the poster wanted an IMAP server. Courier can best be considered
"RFC-aware", rather than compliant.  That snipe offered, it's
pretty much ok as far as most of the commands and behaviors.

> > See http://www.courier-mta.org/mbox-vs-maildir/
> Damningly faint praise.  Why aren't there comparisons against
> real, modern mail formats?
> 
> > PS - Why is maildir no good?
> How many times must this be hashed out?
> 
> File-per-message is expensive, and you can generally only afford
> it on large mail folders when you have a very capable index. 
> Which is why Cyrus does just that.
> 
> > >Me?  I use Sendmail (Inc)'s IMAP server which is cyrus with
> > >performance tweaks and a GUI.
> > 
> > Is this commercial?
> 
> Sort of.  

Drifting off topic, with apologies, for accuracy...

Yes it is commercial.  IIRC, something like $4/user with a 500 user
min and a couple hrs to setup and install and get running.  For
$2500, if I can download it at noon and have it up and running by
3 with a GUI for the secretary to manage all the users and MY not
having to do much other than back it up and debug oddities, that's
worth $2500 of my time.  It's off topic, since it's not a BSD option :(

> If you don't want to spend the money, you just
> download cyrus instead, and do without the GUI.

And without a lot of the speed tunings that reduce stat()ing all
the files.  Sendmail's IMAP server *started* with Cyrus.  Among
other things (and somethings cyrus 2.x now has), cache files with
header info mean that it's generally parsing in ONE file and just
passing that out the wire.  And, as mentioned, the GUI is valuable.
My mom has a domain on my server for her work and adds/deletes users
via the Web.  Mom doesn't not do Unix (yet).  It means that *I*
don't have to do administrivia.

Other niceties are that if a message comes for 20 people, it's
stored once and hardlinked. When you have people sending MP3's or
powerpoint or even list mail to large groups, this can be helpful
and reduces IO.  More important when you have 30k-500k users than
when you have 50.



If you choose Cyrus, DB 3.x (if not 4) is likely the db version
that you want.  Far superior to db 2.x and certainly db1.85.

Also, IMAP is ALL ABOUT DISK.  A set of 15,000RPM disks, striped/
mirrored with a 400MHz CPU will be faster than a 2GHz CPU and cheap
IDE or slower SCSI.

For now, news:comp.mail.imap will give you better info on your options.

I still haven't seen "standalone" defined.  Nor useful info like
"how many users" or "what environment" (dialup users != a LAN full
of programmers != a LAN full of folks mainly doing non-computer
stuff).



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