Stefan Foerster:
> * Wietse Venema <[email protected]>:
> > For STATISTICAL load balancing you can get by with multiple IP
> > addresses per proxy filter "host" name. However this requires new
>
> The main difference I see here is that delivery to a content_filter
> will try more than one server, giving us not only (statistical) load
> balancing, but also some kind of redundancy.
That would work only when the smtpd_proxy client is modified to
use the SMTP connection cache. Otherwise, a connection still has
to time out before the next host is tried. (*)
There is no such performance hit with true load balancers, which
maintain state about which hosts are busy/dead/other.
Wietse
(*) It takes major surgery to make the smtpd_proxy client as smart
as the Postfix SMTP client (address randomization, connection
caching, bug workarounds, and more) Namely, to make the Postfix
SMTP client usable as an smtpd_proxy client.
