John R Levine <johnl(_at_)taugh(_dot_)com> writes:
This leads to the fairly obvious question: if the primary is up 99+%
of the time, what's the point of a secondary? There was an era when
they were useful to deal with networks that didn't have routes to some
parts of the net, but I'd think that's a pretty small niche now.
Unless your primary is down for a long time, days or longer, any
legitimate mail will just wait and retry and get delivered anyway.
My primary is probably up 99% of the time since it only really goes down
every three years or so. However, when it goes down, it's usually down
for days and I want control over the mail in the meantime. I don't know
in advance when it's going to go down, and it may well be while I'm out
of the country or don't have Internet access.
I have control over queue retentions on my secondary and can hang on to
mail until I know I'll be around to address whatever problem is
happening.
--
Russ Allbery (rra(_at_)stanford(_dot_)edu)
<http://www.eyrie.org/~eagle/>