Post: #2

you must set servers name/IP on [SERVERS] section of sphere.ini

this only redirect the client to server IP, it won't transfer accounts/characters automatically between servers. So you must create some advanced sync engine to export the account/chars from one server and import on the other server

but anyway you don't need an 2nd server just to prevent overload on 1st server, sphere can handle 1000+ clients on the same server (or even much more) as far as your hardware performance can handle it. So the best option to maintain an high capacity server is use an high performance hosting instead split sphere in many small pieces