Subject: Re: daily (& security) mail not delivered
To: None <Richard.Earnshaw@arm.com>
From: Andrew Brown <atatat@atatdot.net>
List: current-users
Date: 06/30/2003 10:33:33
>> >    # send stuff from submit queue too.
>> >    /usr/sbin/sendmail -Ac -q0 &
>> 
>> you can run sendmail in non-daemon mode out of cron to flush the
>> client queue to the smtp listener's queue, but that's it.  sendmail
>> won't deliver directly out of the clientmqueue directory, so you'd
>> have to start an smtp listener process at the same time.
>
>Nearly, but not quite true.  If all your mail has to go via a central hub, 
>then you can set the SMSP to send directly to that:
>
>	 FEATURE(`msp', `mailhub.mydomain')
>
>(of course, your mail hub has to be prepared to relay internal mail, but 
>it has to be able to do that anyway.

that's very true, but i doubt it's the "common case".  most people
probably read their nightly reports on the local machine, if they read
them at all.  i know i'm a little slack on some of my machines...

>But that doesn't work if you need local alias processing, since that's 
>only done by the main sendmail daemon, not the submission daemon.

also true.

>This is all quite disastrous on low-memory machines, I now need sendmail 
>running on my machine just to be able to redirect local root mail to 
>myself (the main mail servers send root mail to the sysadmins), and that 
>daemon is wasting nearly a Meg of RAM and a process slot (according to 
>'top').  Postfix isn't any better in this regard.  It has something like 
>three daemons running in the basic dumb-client configuration.

well, yes, but then you don't suffer as much in startup costs whenever
sendmail is invoked to collect local mail, since most of the memory
will end up shared.  but that's a silly argument.

your point about postfix is true, but conversely, under high load,
postfix has a better memory footprint than sendmail.  sendmail starts
lower tehn postfix, but grows more quickly with load.  postfix starts
higher, but its growth curve is much shallower under load.  for
whatever that's worth.

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