----- Original Message -----
From: "Wietse Venema" <wie...@porcupine.org>
To: <postfix-users@postfix.org>
Sent: Monday, March 23, 2009 7:42 PM
Subject: Re: Mail drop
Victor Duchovni:
On Mon, Mar 23, 2009 at 07:24:50PM -0400, Wietse Venema wrote:
> Victor Duchovni:
> > and may be causing high disk latency. You have to tune the milter
> > configuration
>
> There is no need for dkim-milter to touch the disk. It receives
> header and body content from Postfix via the Milter protocol. I
> know this, because I implemented the Postfix side of the protocol.
No need perhaps, but does that prove that no disk I/O takes place? I am
not saying there is disk I/O, but lack of need is not lack of use. So
that should be excluded. If the disk is not saturated, perhaps there
are DNS lookups or other sources of latency.
dkim-milter does not store the email message outside the mail queue.
In signing mode, it receives the headers and body from Postfix,
and then it asks Postfix to add a message header with the DKIM
signature.
dkim-milter does not use DNS lookups while signing mail. It has
a copy of the private key.
dkim-milter does of course use DNS lookups when verifying signatures.
It is possible that he is running it in verify mode, and that his
DNS has a 13ms round-trip time over a slow 128kbps ADSL uplink.
But it seems unlikely.
We're just signing. No lookups.
Tracing the system calls in the milter may help (when sending just
one message to reduce confusion).
strace-ing a multi-threaded program, have fun.
Wietse
