Old topic to be discussed.
Slaving the following zones from the root name servers has some significant advantages:
1. Faster local resolution for your users
2. No spurious traffic will be sent from your network to the roots
3. Greater resilience to any potential root server failure/DDoS
On the other hand, this method requires more monitoring than the hints file to be sure that an unexpected failure mode has not incapacitated your server. Name servers that are serving a lot of clients will benefit more from this approach than individual hosts.
great! now Bind 9.9.0 supports raw file for slave zone.
 FreeBSD's /etc/namedb/named.conf