= Postfix/Heavy_duty_local_delivery =

From http://archives.neohapsis.com/archives/postfix/2009-11/0170.html

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User wants to delivery a lot of stuff to a local pipe, but it's topping out around 200-300 per second. When the postfix queue starts to fill up, it all goes to shit.

Posters point out that his disk subsystem can only do a couple hundred fsync()s per second, which is probably what they're running into.

From Victor: {{{
Stop right there. At 200 msgs/sec, fork/exec of scripts via local(8)
is never going to give you the right performance. You need (in addition
to the faster disks already mentioned), to use a resident (pre-forked)
SMTP or LMTP server script to receive the mail in question.
   - Do not use local(8)
   - Do not start a new interpreter process for each message
}}}

And a saner solution: {{{
Does this application really need Postfix and a queue? Why not just
turn the script into an SMTP server that pre-forks a fixed number of
copies and loops receiving/processing email? For 200-300 msgs/sec on
an I/O constrained server with a single "mailbox", one really does not
need Postfix, and can't afford the I/O cost of a local queue.

You are not going to succeed without more spindles and likely more CPUs.
Just launching a "Perl" hello-world script takes >10ms on a fast machine,
do that 100 times a second and you've burned a CPU, and non-trivial
scripts are slower still.
}}}

Also of note was that he could just throw a metric fucktonne of disk spindles at the problem.