lammert - 11:35 am on Jul 1, 2010 (gmt 0)
Having the DNS records on a separate DNS server can be good in times when your server crashes. With a webserver crash, you can change the DNS records to a new IP address where you have uploaded a recent backup of the site, and then start to recover the old server. Users will be redirected to the new IP address. If both the sites and the DNS records reside on the same server when a crash occurs, recovery can be much more difficult.