Re: [exim] heartbeat load balancing and exim

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Autor: Jeroen van Aart
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A: exim-users
Assumpte: Re: [exim] heartbeat load balancing and exim
Wouter Verhelst wrote:

> It is properly supported by exim upstream, and the recommended course of
> action in case you need a clustered setup. Exim deals correctly with the


There are those, enough of them, who disagree. As I said countless
discussions can be found, like this one:
http://mailman1.u.washington.edu/pipermail/imap-uw/2007-September/001574.html

> multiple quirks that are part of the NFS protocol, such as certain
> locking mechanisms not working (exim uses the one that does work on
> NFS), the fact that the filesystem may not be available when exim tries
> to write to disk (in which case exim will delay delivery, or return a
> 4xx response depending on what file it wants to write), and the fact
> that multiple queue runners may be active at the same time (which is not
> a problem even if you do it on the same host).
>
> Exim does not 'sort of' work with NFS. Exim works great with NFS. Even
> if you want to write to mboxes over NFS, exim will not corrupt them
> provided you set your transport up to use lock files rather than flock


I am sorry but you perfectly point out why NFS would be a bad idea. It
requires exim to work around NFS' flaws instead of just working, like
when it'd access a real filesystem. How can you say exim works great
with NFS if you have to set up your transport to use lock files rather
than flock, or else files may become corrupted. That to me sounds like
it does NOT work great, but works sort of, if you're careful and avoid
the problems.

In that same line of thought qmail works great IF you apply the 600 or
so patches it needs to actually turn it into something resembling an MTA.

Regards,
Jeroen