If you are looking for the options to avoid any DNS-related downtime or the way to manage dns across all server you have, you might consider to setup master-slave DNS cluster.
1. Create user dns-cluster on a server which will be used as dns slave
2. Run following command on a master:
v-add-remote-dns-host slave.yourhost.com 8083 admin p4sw0rd
Password and host name should be replaced with relevant data of course.
This way you can set up master->slave or master-master-master cluster. There is no limitation on how to chain dns servers.
