While trying to setup up my VPS, I came across the name server settings.

Most of what I found online were regarding how to setup name servers, which advised something like `ns1.mydomain.com` and then my IP address.

Why should I setup a name server as above (as opposed to what is currently default set by provider)?

Why should I create a second name server like 'ns2', and should it be a different IP or the same as 'ns1'? (If the IP for 'ns1' and 'ns2' match isn't that redundant?)

The cPanel has name servers—do those have to match the domain name servers?