W. Michael Petullo:
> My mail spool is not on my root directory:
>
> data_directory = /mnt/xvdb/var/lib/postfix
> mail_spool_directory = /mnt/xvdb/var/spool/mail
> queue_directory = /mnt/xvdb/var/spool/postfix
> virtual_mailbox_base = /mnt/xvdb/var/spool/mail
>
> However, it seems that the capacity of my root mount has some bearing
> on the evaluation of Postfix's message_size_limit and queue_minfree. I
> am getting "insufficient system storage" errors despite having enough
> space in /mnt/xvdb. I have much less space available on /.
>
> I found some relevant functions in Postfix: fsspace() and
> smtpd_check_queue(). I also wrote a program confirming my understanding
> of fsspace()'s use of statfs().
>
> Before I continue diving into Postfix's source code, can someone provide
> some information about the details surrounding message_size_limit and
> queue_minfree? Is my assumption valid that the capacity of / should be
> irrelevant when my spool is on /mnt/xvdb? Is there another directory I
> should be concerned about other than the four listed above?
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.
