How can I do like this? (two hubs in same network)

[Xerxes]

Hello.

I want to place 2 hub servers to backup each other.

For example, irc network should be okay even if either server1 or server2 dies.

and how can I set DNS settings to do like that?

Thanks for your help!

Have a nice day

[warg]

Compile both servers as hubs, and link them together as normal, and configure their link blocks as you would for a hub.

What you're asking about DNS is called a round-robin. You give multiple A records with the same name.

For example...
irc.domain.tld. IN A 192.168.0.100 irc. ... .168.0 300

When a client connects to irc.domain.tld they will then connect to a random IP.