Doubts about BIND
kcd at chrysler.com
Tue Jun 2 22:53:22 UTC 2009
Eduardo Júnior wrote:
> I have some doubts about BIND and can't find documentation about:
> References are welcome =)
> 1. The Named read the file named.conf and store all it in the main memory?
> The same is done to files zones?
Yes, basically, in the default configuration.
> Or is there another way?
Another poster pointed out the optional DLZ mechanism, which allows one
to use a database backend with BIND.
Frankly, I'm not sure why anyone would do this, at least from a
cost/benefit standpoint -- memory is cheap, but setting up and
maintaining enterprise-strength databases typically *isn't*.
I suppose there might be niche uses, if one wishes to monkey around with
the data dynamically...
> 2. Once named.conf and files zones are loaded in memory (if they are
> put there), the search for some domain
> is sequencial?
No, it's not sequential. It's optimized for looking up "tuples" of
information (name, class, type) organized in a hierarchical tree.
I don't think BIND _ever_ implemented "sequential" lookup, if by that
you mean it looked through every record set in every zone, until it
found the one it wanted. That would be grossly inefficient. At the very
least, some sort of crude binary-tree structure would perform much
better than sequential lookup.
> 3. When I have N threads of the named listening on port 53, is there a
> internal queue of requests to named? If yes, how they are managed?
Perhaps someone more familiar with the code can elaborate, but on the
surface it seems to me to follow the standard multi-threading model of
having one thread as a "listener", which then dispatches to "worker"
> Are there queues to files zones too?
No, the data is in memory, there is no need to "queue" direct memory
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