bind9: debugging information in logs

[Pavel Sukhoy]

Hello,

Could you please give me clarification about debugging mode. 

In the BIND9.7 ARM I found this:
"...
The server can supply extensive debugging information when it is in debugging mode. If the server’s
global debug level is greater than zero, then debugging mode will be active. The global debug level is
set either by starting the named server with the -d flag followed by a positive integer, or by running
rndc trace. The global debug level can be set to zero, and debugging mode turned off, by running rndc
notrace. All debugging messages in the server have a debug level, and higher debug levels give more
detailed output. Channels that specify a specific debug severity, for example:
channel specific_debug_level {
file "foo";
severity debug 3;
};
will get debugging output of level 3 or less any time the server is in debugging mode, regardless of
the global debugging level.
..."

But on the BIND9.7.2-P3 I have seen that: if only "severity debug [level]" will be set in channel configuration and at the same time debugging level is 0 - I will see in log file information regarding to this debugging level. I think something is wrong. 

-- 
With best regards,
Pavel Sukhoy