>>> If in doubt, RTFM?
>>>
>>> queue_minfree (default: 0)
>>> The minimal amount of free space in bytes in the queue file system
>>> that
>>> is needed to receive mail. This is currently used by the Postfix
>>> SMTP
>>> server to decide if it will accept any mail at all.
>>>
>>> By default, the Postfix SMTP server rejects MAIL FROM commands when
>>> the
>>> amount of free space is less than 1.5*$message_size_limit (Postfix
>>> ver-
>>> sion 2.1 and later). To specify a higher minimum free space
>>> limit,
>>> specify a queue_minfree value that is at least
>>> 1.5*$message_size_limit.
>> I did indeed read that. What puzzles me is that it seems my spool
>> filesystem seems to have plenty of space. My root filesystem does not,
>> but as I understand things that should not matter.
> What is the output from
>
> df -k
> postconf queue_directory message_size_limit queue_minfree
>
> on the Postfix machine?
I found the source of the problem. What I did not realize is that the
OpenWrt package I use is patched to modify the call of fsspace() in
smtpd_check.c (I had been looking through the upstream source).
The OpenWrt patch hard codes fsspace("/overlay", &fsbuf), because
OpenWrt installations often make use of an overlay filesystems, mounted at
"/overlay". This makes sense in some cases, but obviously not when the
mail queue exists on a big, separate disk.
I suspect that this patch should be modified to be more careful, and I
also think its likely best kept as a per-distribution modification. The
reason I say this is that the layout of things, including the /overlay
mount point is distribution-specific. Thus a more robust logic is
required, but it probably belongs in a distribution-specific patch.
I wanted to follow up because it is possible that someone else might
run into this problem. I also wondered if there was an opinion in the
Postfix community about where to handle this edge case.
For further reference, here is an issue I submitted against the OpenWrt
Postfix package:
https://github.com/openwrt/packages/issues/9970
--
Mike
:wq
