On Wed, Oct 15, 2008 at 03:48:18PM -0400, Ofer Inbar wrote:
> Victor Duchovni <[EMAIL PROTECTED]> wrote:
> > > So I wonder if any of you administer high volume postfix sites and
> > > have run into the same problem, and if you've found any workarounds.
> >
> > The work-around is to get on the Yahoo whitelist.
>
> I should've mentioned that all servers in question are whitelisted.
>
> Obviously if they weren't they'd be having problems with the other
> large ISPs too, so I thought it was implicit (large volume sites get
> on the relevant whitelists or they just don't work). Sorry.
In that case, you should post summary statistics from the
delays=a/b/c/d
log entries for yahoo. The "a" and "b" numbers don't really matter in
this context, but "c" and "d" are critical. Simple averages distort the
picture because one slow message can hide a lot of fast messages. So I
tend to compute "moving averages" with slow exponential decay, yielding
output similar to the below:
$ perl -lne '
m{\A\S+T(\S+).{5} \S+ \S+: \w+: to=<[EMAIL PROTECTED]>, (?:orig_to=\S+,
)?relay=\S+, (?:conn_use=\d+, )?delay=\S+,
delays=[\d.]+/[\d.]+/([\d.]+)/([\d.])+,} or next;
$c = 0.95 * $c + 0.05 * $2;
$d = 0.95 * $d + 0.05 * $3;
if (++$i % 100 == 0) {
printf "%s %5.2f %5.2f\n", $1, $c, $d;
}' maillog
13:01:39 6.30 5.07
13:05:59 7.24 4.70
13:12:06 4.58 5.39
13:16:15 1.28 4.73
13:21:56 1.71 5.20
13:27:33 0.50 4.88
13:33:35 9.90 4.78
13:37:57 3.82 4.80
13:41:40 0.70 4.47
13:48:30 4.72 4.56
13:54:10 5.50 5.22
13:58:01 6.15 5.25
So, it looks a single connection to Yahoo! takes approximately 5 seconds
to setup, 5 seconds to deliver each message, and (if your message rate
is high enough) capable of delivering up to 5 messages. So for me,
maximal throughput per unit of concurrency is:
msgs/sec = 5 / (5 + 5 * 5) = 1/6
If my destination concurrency to Yahoo! is the default 20, (not sure
they let you make that many connections from the same IP) I can only
deliver 20/6 ~= 3 msgs/sec per sending host.
To send 100 msgs/sec, I would need ~30 hosts. Fortunately, I don't have
nearly that much demand for mail to Yahoo!
--
Viktor.
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