sendmail performance question

[Craig White]

On Fri, 2002-04-05 at 13:43, David A. Sinck wrote:
> 
> I could stand a few pointers here, as I've reached the bottom of my
> idea barrel and I've got splinters from scraping the bottom.
> 
> Synopsis:  
> 
> sendmail on a dual p3/733 w/ 1G + scsi is 30% of the speed of a p3/667
> w/ 512M + ide.
> 
> That just doesn't seem right; I want to know why.
> 
> If you're not interested, this would be a good time for the D key :-)
> 
> 
> Details:
> 
> Common:
> * same perl version
> * same perl Net::SMTP version
> * same sendmail + sendmail configs (md5sum the same)
> * same input (1k test messages)
> * same network (xxx.3 + xxx.4)
> * same nics
> * both 'mostly idle'
> 
> Slow:
> * dual p3/733, 1G, scsi
> * 5+m return
> * kernel 2.4.9-13smp  (redhat)
>  
> Fast:
> * p3/667, .5G, ide
> * 1+m return
> * local dns server
> * kernel 2.4.9-12 (redhat)
> 
> 
> The slow box uses the dns server on the fast box...and peculiarly, dig
> against it comes back faster reliably based on hand tests when the dns
> server is accessed remotely.  (1-2ms vs 3ms).
> 
> hdparm: buffer cache faster on slow box (scsi) (2x) but slower on
> buffered disk reads (1/2) vs the fast box.
> 
> I reluectantly downed the local firewall on the slow box (albeit still
> behind a router/firewall, I'm not completely insane :-), but that
> didn't change the performance.
> 
> It *appears* as if the box with the local bind on it is forking
> sendmail 3-4x what the non-binded box is, which would account easily
> for the performance....  But if the configs are the same, how is that
> possible? 
> 
> Ideas?  Preferably good ones?
-----
OK - speed issue is vague.

If you are talking about a localhost send, then perhaps it is the time
with which to resolve the sending host - check the file /etc/hosts to
make sure that 127.0.0.1 localhost.localdomain localhost is included and
that the hostname resolves internally.

If you truly believed that it was merely a matter of having bind locally
on the machine, it wouldn't take long to install a version of bind and
set it up as a caching server - but then there is the issue of the bind
cache itself, after the domain has been resolved, things are infinitely
faster until it expires.

I am curious that the sendmail config files are the same - how could
both machines be willing to accept the mail for the domain in the same
manner? That really doesn't make sense - did you generate them both from
the same /etc/mail/sendmail.mc ?   Do they both have the same directives
to use the same /etc/mail/access ?  Are they both using the same version
of db3 or whichever db it is that sendmail uses to hash the
aliases/access/virtusertable etc?

Craig