Now, if you lost power and you are waiting on DNS and NIS servers to come back online, who is accessing your servers anyway?
The answer is in the message to which you were replying:
... then lets say you have a power outage. The filer comes up and then can't do anything because it's waiting to talk to the NIS server (it's probably the DNS server too). The NIS server can't do anything because it's waiting to mount the filer. Stalemate.
The filer is trying to access the NIS server, in response to the NIS server's mount request (needed to access the NIS data).
This sort of power-up interdependency is a royal pain when managing a large installation. As Bruce notes, moving key data like DNS and NIS off the filer to local disk goes against the idea of having all of your data in a central, secure place.
Back when I was a customer of NetApp's, the way I solved the problem was to have the master data on NFS storage (we were just starting to buy filers when I left) but have slave/secondary servers which used local disk and which had no external dependencies for their core functions -- essentially, we turned SPARCservers into appliances for DNS, NIS, etc. If any of them roached their data, we could always bring the world up using other ones and then once the master was back rebuild the dead slave/secondary.
-- Karl