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postfix-users: Re: Queue full of double-bounce

Re: Queue full of double-bounce

From: Wietse Venema <wietse_at_nospam>
Date: Mon Oct 11 2010 - 15:43:30 GMT
To: Postfix users <>

> Apparently the low-frequency $queue_run_delay (300s) timer still
> works, so the queue manager picks up one message every 300s, but
> your system's ZERO-DELAY timer support is broken, so the queue
> manager does not pick up the next message immediately as it does
> everywhere else.
> Thus, you're limited to about 288 deliveries per day.
> What OS platform is this? What about virtualization? What about
> tick-less timer support? What Postfix version, any "improvements"
> made by local users or helpful vendors? RedHat used to be pretty
> good at breaking Postfix in surprising ways.

Patric Falinder:
> I'm running Debian Lenny x64 with Postfix 2.5.5 with VDA patch.
> It's virtualized on a VMWare ESX server.

Uh-oh. Yesterday there was a post about lost timer interrupts with
VMWare ESX that affected idle processes where the $max_idle timer
didn't go off.

> How do I fix the system's ZERO-DELAY timer?

I can write a small test program. If it reproduces the problem,
then there are two things that need to be done.

1) The program needs to be sent to VMware as part of a bug report.

2) We can try to program around this bug until the vendor fixes
it. Perhaps some system configuration will suffice. For example,
many virtualization systems emulate a number of "hardware" timers
such as ACPI, TSC etc. and some emulations may be less buggy.

But first, you need to get some recent Postfix source code on the
machine so that we can do some quick tests. There is no need to
overwrite the installed Postfix.