On Thu, 16 Nov 1995 17:17:16 -0500 Paul Graham <[log in to unmask]>
said:
 
>We're one  of the  (apparently) few sites  running listserv  (1.8b) with
>sendmail (8.7.1) on sun equipment (under solaris 2.4). I'm interested in
>any  experience   tuning  and   or  driving   sendmail  for   the  ~200k
>connection/day range.
 
Perhaps the following chart might help:
 
********************************************************
* Top 20 sites by volume delivered daily (NOV95, 1-17) *
********************************************************
 
Pos Recipients  Site
--- ----------  ----
  1    1301411  PEACH.EASE.LSOFT.COM (Windows NT 3.50 + LSMTP V1.0a)
  2     281181  LISTSERV.SYR.EDU (Solaris 2.4 + LSMTP V1.0a)
  3     267072  UGA (VM/ESA 2.2)
  4     243617  UKCC (VM/ESA 2.2)
  5     223687  UBVM (VM/ESA 2.2)
  6     208609  LISTSERV.ACSU.BUFFALO.EDU (Solaris 2.4)
  7     193839  NDSUVM1 (VM/ESA 2.2)
  8     183964  AMERICAN.EDU (AIX 3.2.4)
  9     176027  MAELSTROM.STJOHNS.EDU (OpenVMS V6.2 + LSMTP V0.1a)
 10     174842  CUNYVM (VM/ESA 2.1.0)
(etc)
 
Syracuse used to run sendmail and may be able to help you. I also believe
AOL has a number of  non-LISTSERV machines doing about 200k/day (although
it's mostly incoming mail so it might be a totally different situation).
 
>I end up with  rather peaky use curves and it seems if  I could keep the
>load at the  average value I'd actually be able  to deliver to 1,000,000
>recipients daily.
 
It's  not that  simple unfortunately.  If one  could keep  the load  flat
constant over  a 24h cycle,  even a small  machine would do  wonders. But
most of the mail  comes during business hours and in  general if your 24h
average is X deliveries per hour, your  most busy hour will show about 3X
deliveries.  Again roughly  speaking,  if  your machine  can  do Y  daily
deliveries on a flat 24h input flow model, you can process a Y/2 workload
with mediocre performance  and a Y/3 workload with  good performance. For
instance, back when I was running SUNET's traffic using sendmail, I had a
PC that  could handle 360k/day  provided that  the mail came  in smoothly
enough and there was no outage,  etc. I was getting good performance with
my workload  of ~100k/day  (at the  time) and my  peak hourly  rates were
12-15k/hour depending on  the day. Sometimes I got 120k/day  and this was
still working ok. I knew I could  do 150-180k/day and this would still be
ok, but there's no way I'd be able to run a real workload of 360k/day. It
would have  meant overnight  delivery in  the *best*  case and  the users
would have  killed me :-) And  then there's the queue  build effect which
slows down everything, and of course  the fact that the higher input load
during  peak hours  causes  paging or  otherwise  decreases the  absolute
efficiency of the delivery system during the day.
 
Anyway, 1M/day  with a flat input  model means about 333k/day  usable. So
I'm not sure there's any major  conflict between the theoretical peak and
the ~250k/day you are actually observing.
 
  Eric