Re: [Exim] Reliability of spool/delivery handling (Linux)?

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Author: Greg Ward
Date:  
To: exim-users
Subject: Re: [Exim] Reliability of spool/delivery handling (Linux)?
On 21 August 2001, Philip Hazel said:
> I'm afraid I don't have enough knowledge/understanding to follow how or
> why that is relying on whatever it is that is worrying people. My
> understanding of rename() is that it is atomic, that is, from the point
> of view of other processes, either it has happened or it has not. There
> is never a halfway state when neither the old file nor the new exists.
>
> If there really is a problem, please can somebody explain it to me in
> more detail?


I don't understand it either, and I wish I did. The ReiserFS FAQ (at
www.namesys.com, which is down as I write this -- argh) mentions
something about Qmail on ReiserFS being problematic because of certain
assumptions Qmail makes about the atomicity of certain filesystem
operations. At a round-the-water-cooler discussion this afternoon, I
learned that Postfix makes similar assumptions, and ext2 (the main
filesystem for Linux) similarly does not meet those assumptions. Now we
learn that Exim is in the same boat as Qmail and Postfix, and ext3 (an
update to ext2 which adds journaling) is in the same boat as ReiserFS
and ext2. But I still don't understand what those various boats are
really about at a nitty-gritty level.

Blind-leading-the-blind...

        Greg
-- 
Greg Ward - software developer                gward@???
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