Thank you for providing this information. I would greatly appreciate it if you could generate a tutorial on effectively utilizing multiple servers to address downtime. I apologize for my lack of experience in this area, as I'm unsure of the appropriate terminology to use, but I'm eager to learn and understand the concepts fully.
But you still have to enter ALL four Nameservers at the registrar? If you had 20 servers you would need to enter 40 nameservers at the registrar? IS there a way to have 2 NS, and move the sites within a pool of 20 servers? Without having to change the nameservers at the registrar? I am looking for a solution where I ask clients to point their domain NS to us, but we manage where they are hosted at will.