On Thu, Jan 14, 2010 at 05:09:03PM -0500, nixlists wrote:
quoted text
> On Thu, Jan 14, 2010 at 4:26 PM, Denis Doroshenko
> <denis.doroshenko@gmail.com> wrote:
> > On 1/14/10, nixlists <nixmlists@gmail.com> wrote:
> >> Does it have the same reliability features as qmail on an FS without
> >>  softupdates? What about with softupdates?
> >>
> >>  http://cr.yp.to/qmail/faq/reliability.html
> >
> > the very link you just provided contains the following sentence:
> >
> > Do not use async or softupdates filesystems.
> 
> 
> Sorry, forget I mentioned softupdates. Does it do what qmail does?
> Reliaibility-wise?
> 
> "qmail's queue, except for bounce message contents, is crashproof on
> the BSD FFS and most of its variants. "
> 

smtp ensures reliability by working on a temporary queue during writes,
then commiting messages (all of them, including bounces) to the real
queue using an atomic rename. after a successful rename, smtpd tells
the client it accepted the message.

with this ordering, you can never have smtpd in a state where it has
lost a message after accepting it or where a message is incomplete and
corrupt in the queue because of a power shortage happening at a wrong
timing. either the message is in queue or it's not, and if it's not
then client/mua was not told message is accepted.

Gilles

-- 
Gilles Chehade
freelance developer/sysadmin/consultant

		   http://www.poolp.org