High loading of bind

[Hans]

> when the dns no response, the cpu loading is 1or 1.1 and name process 
> usage 49.5% , network usage 1.6M, query about 460 per second

Why are you not running Bind 9 ?
There is something very wrong.
I use the same boxe's but these box go over 8000 query's a second without 
any pain.
Please remember that an bind 8 server will not answer duriing zone reload's.
But that you see in the logfile.