OSEC

Neohapsis is currently accepting applications for employment. For more information, please visit our website www.neohapsis.com or email hr@neohapsis.com
 
Subject: Re: Problem processing mail while rebuilding virtual map(s)
From: Wietse Venema (wietseporcupine.org)
Date: Mon Sep 18 2000 - 08:33:19 CDT

Are you using db tables? Postfix locks files to avoid surprises in
the middle of an update, but changes in-between locking attempts
are not necessarily noticed. This should not be a problem with dbm
files.

If the problem is with db files, try renaming the files into
place rather than overwriting them (an atomic rename does not
exists for file pairs like dbm).

        Wietse

Kurt Andersen:
> I have spotted a problem that can occur when rebuilding the virtual
> maps (hashes) on a busy postfix server. Background: for various
> reasons, we have a process that runs on a daily or more frequent
> basis to push new copies of a master virtual map out to our mail
> handlers. The process pushes out the text version of the file and
> then calls postmap to compile it into the binary version.
>
> Postfix then gradually recognizes that the map has changed and kills
> off the daemons so that they will pick up the new information. The
> problem appears to be that the cached information (or map handle) can
> be invalid prior to the process being killed. I have observed that
> mail is being bounced with "user unknown" reported by qmgr in the
> interval after some of the daemons are killed off but before the
> specific qmgr has been killed.
>
> Of course, the specific users in question (or complaint) are ones
> that haven't actually changed so they don't understand why they are
> being picked on.
>
> I'd be happy to use our setup to run some more thorough testing to
> characterize the problem if someone can suggest something. I'm
> leary of just turning on -v for the qmgr since one of the keys to
> the problem is that the system stays quite busy (>20 msg/min average
> over the entire day).
>
> Thanks in advance for the help...
>
> --Kurt
>
>
> --
> Kurt Andersen <kurtaspk.agilent.com>
> Agilent Technologies Postmaster
> Global Messaging Team, Agilent Technologies
> (509) 921-3792
>
>
>
>