Majordomo is working as designed, but the mailing list server and
mailserver are getting somewhat overwhelmed by having enormous clots of
list thrown at them at the same time on Mondays and Fridays.
I am wondering if anyone has implemented or knows of anyone implementing
a throttling/priority dispatch. I have two features in mind:
1) to throttle output
2) to attach priority to mailings. I wonder what I'd do if I had a
queue full of mailings and an emergency came up that I had to get out a
mailing immediately
I /am/ already using a wrapper for bulkmailer (because without it, all
the bm submission fail on Draining Input) and I suppose I could use the
wrapper do something like check the load, and if excessive, insert a
-sendmail -0dq flag in the bulkwrapper invocation. Anyone with better
ideas?
Background =======================================================
My machines are running AIX V5.2 and sendmail V8.11. When things get
bad, we'll see 125-175 mailings of about 100-400 recipients in each
mailing dropped in the hopper within the span of 30-45 minutes. This is
a rather free-thinking college, which means we have very little ability
to control the users.
Before we (recently) put in bulk_mailer in the mailing list server, its
throughput limitations served to throttle what was coming at the mail
server...it would run for 2-3 hours to chew its way through the mailings
log jam and it didn't much impact the college mailserver. But mailings
were getting through in a timely fashion and recently I realized that
some mailings weren't getting through during the peak load periods...
getting lost due to the drop that happens when you see the dreaded
"Timeout waiting for input from local during Draining Input"
Now, with bulk_mailer, the mailing list server chews through in
something like 30-45 minutes, there are no Draining Input messages,
though I do see, during peak loads, a bulkmailer failure syslog message:
Sep 9 16:18:37 shell sendmail[1556506]: j89GHfY245932:
to="|/usr/local/bin/bulk_wrapper owner-stu07@bard.edu
/usr/local/majordomo/lists/stu07", ctladdr=stu07-doit (1/0),
delay=00:00:56, xdelay=00:00:48, mailer=prog, pri=290194, dsn=4.0.0,
stat=Operating system error
Even so, this does get queued, so it does get sent a bit later.
OTOH, this greater throughput makes the load on the mail server a lot
heavier. Before it wasn't really noticeable, but now the load of a mass
mailing hits the mail the mail server hard. Used to be, its CPU rarely
got over 20%. Now the increased throughput means the mail server's Cpu
can go to 70 %.....
Any ideas?
--
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Stewart Dean, Unix System Admin, Henderson Computer Resources
Center of Bard College, Annandale-on-Hudson, New York 12504
sdean@bard.edu voice: 845-758-7475, fax: 845-758-7035
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