[Dovecot] Temporary files

Steven King sking at kingrst.com
Thu Jul 15 00:02:50 EEST 2010

On 7/14/10 4:34 PM, Timo Sirainen wrote:
> In v1.0 .. v1.1 deliver was writing incoming >128k mail to /tmp file (to
> avoid reading it all into memory). In v1.2 I moved it to user's home
> directory. This slowed deliveries for NFS users. Also people with
> filesystem quota had trouble since now user required twice as much
> available quota to save a message. The FS quota problem was "solved" by
> having quota-fs plugin change the default temp file path to /tmp.
> So why was the move made in the first place? Because a) some people had
> small (maybe ramfs) /tmp and Dovecot was eating it all up and b) to
> avoid any potential security issues with storing per-user files to a
> shared directory.
I haven't seen anywhere that /tmp is actually a ramfs, but that is
besides your point. I would say that if people are using Dovecot they
should be designing the partitions around the need for the software and
services they are running (at least that is what I do).
> I'm now thinking about a new setting (mail_temp_dir?) for v2.0 where
> these temp files would be stored (lda, lmtp, some others in future).
> Maybe the b) problem isn't that huge, so maybe there doesn't need to be
> a way to store them to user's home. So that leaves a) problem. Maybe the
> setting could default to /var/tmp instead of /tmp? That probably has
> more disk space available usually. (I hope /var/tmp is available
> everywhere?)
Everywhere I have seen /var/tmp used, it has been linked to /tmp. I
would recommend using /tmp as the default. Also, not all distributions,
including Slackware (which a lot of slack users like Dovecot) do use
/var/tmp for anything, which can get confusing.

I really like the idea of a default, and then the ability to change the
default. That way if people need to grow out of /tmp or wherever you
decide the default is going to be, it can be moved easily.
> Any thoughts?

Steve King

Senior Linux Engineer - Advance Internet, Inc.
Cisco Certified Network Associate
CompTIA Linux+ Certified Professional
CompTIA A+ Certified Professional

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