Multiple servers and ip addresses

I have 2 seperate VDS accounts with 2 different providers.
The first one is a 1 gbmem based setup with 4 ip addresses, the second is a 2 GB setup with 3 ip address.
I have virtualmin/webmin installed on both and running a couple of sites on each . so far so good!
Each VDS runs its own dns servers. (When I do a dns check on any site it tells me I have too few name servers etc)
I was wondering if it is possible to link the 2 systems so I could run a dns servers to handle ALL the domains, and possibly a backup to each other etc. 2 different physical servers for each DNS. Ns1 and Ns2 etc
Ideally I’d like to use each server as backup for the other with all data in case of failure. Neither server is used to anywhere near its potential at the moment.
The trouble is I have not found any info relating to this type of idea especially using virtualmin etc.
Can a DNS server on VDS1 point to a domain on VDS2 and vica versa. And can I have 2 copies of a virtualsever, one on each VDS and sync them?

Both VDS are running Centos 6.5 and Virtualmin 4.09.gpl GPL

Yes, that will work fine. Actually that is actually how DNS should be configured. You should have at least 2 DNS servers running in different networks. You probably already know that domains require at least 2 DNS servers to work, but what you don’t know is that most people just install both of this nameservers in the same server which is plain wrong.

So in your case, you already have the correct setup. You can setup dns1 in one server, and the dns 2 in the other server. One will be the master, the other the slave. Then all your domains can use your DNS servers name, it does not mater where they are hosted. You should have proper knowledge of how BIND works, network and DNS. If you are not up to learn it or read tons of documentation it would be way easier just to hire some DNS service or use the one your provider has since most providers and even domain registrars provide DNS services for their customers this days.

I use an external dns manager zonomi, free to dirt cheap based on how many records and zones you enter.
Its great for experimenting as u can set the ttl as low as 60 sec.

I can now jump from server to server disabling binds.