Autor: michael Fecha: A: exim-users, sdjl Asunto: Re: [Exim] Opinions sought: Exim and MYSQL > 2. Specification of host, database, user, and password
> Just a note. I was poking around in the openldap libldap implementation > last night and verified that if you define multiple A records for a server
> (round-robin DNS) the library will automatically iterate across the list
> looking for a successful connection. [Note it only attempts a single
> connection to each host.]
>
> So defining round-robin DNS to get at multiple servers achieves both load
> balancing and redundancy.
This is (should) genereally done if you open a TCP connection to a host.
Besides rotating record sets Bind 8 even allows ordered sets, but the
exim patch is still needed: A connect may work, but the bind or the
query itself may fail, because the server shuts down. In this case,
exim will try the next server and that's very important.
Using the new exim feature, you can also first ask a local server,
and if that fails, ask servers in a record set to spread the load.
