Re: [Exim] Washington mbx again

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Author: Nigel Metheringham
Date:  
To: Paul Robinson
CC: exim-users, exim-users
Subject: Re: [Exim] Washington mbx again
paul@??? said:
> My point is that swap space usage is determined by the Operating
> System, not the MTA or the type of mail spool format you use. If you
> use an OS that like to swap out idle processes then an idle mail
> delivery process (!!?!?) will take up swap.


I think this is a case of semantics arguments. Exim's memory
requirements are not going to be greatly affected by the delivery spool
type. However pop daemons' memory requirements vary dramatically -
many of the mbox format handling use *huge* chunks of memory (ie the
size of the mailbox) as well as sometimes making a temp file the same
size as the mailbox (cucipop is an honourable exception here). IMAP
servers are likely to be worse - I would guess the courier server will
either have to parse and read all the messages (storing at least the
headers) in a mailbox on startup or change folder, or hit the disk very
hard on all sorts of IMAP operations.

> Just out of curiosity, does anybody know of a POP3 daemon that has the
> functionality of the mysql-exim-qpopper patch, but uses a
> maildir-friendly pop3 daemon instead? Let me guess - this is another
> one I'll be writing myself from scratch then... I love spending my
> evenings with a pile of RFC print-outs, don't you? :-)


The qmail popup & pop3d programs with separate authenticator, and the
courier imap programs (work the same way) allow very easy
implementation of a different authenticator - eg the qmail one takes
the username/password set it is fed, authenticates/verifies it, sets
the environment for the main pop daemon and then exec's it.

    Nigel.
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[ Nigel Metheringham                  Nigel.Metheringham@??? ]
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