Sharing zones between views to conserve memory

Kevin Darcy kcd at
Wed Jan 9 23:34:05 UTC 2013

On 1/9/2013 10:57 AM, Carl Byington wrote:
> Hash: SHA1
> On Wed, 2013-01-09 at 14:37 +0200, Jan Gutter wrote:
>> So, here's my question: is there a way to share zones between views to
>> conserve memory?
> One way is to put the master copy of those large zones in one view, then
> define those zones in the other views as type 'forward', forwarding to
> localhost.
Yeah, I've done that before, but it has some undesirable caching 
behavior, i.e. entries get cached in the view which forwards, so clients 
can get responses from data that is not as "fresh" as they might get if 
the data were authoritative (assuming NOTIFY is in place, or some sort 
of fast replication mechanism). Also, some things care whether the AA 
flag is set in responses.

I've also been told that at least one BIND-based DNS management system, 
to which I'm planning to migrate, will divide up the available memory 
for named equally, among all of the views defined in the config. So, if 
that's true -- and I haven't been able to independently confirm it -- 
then there would be a limit to how much memory a given view can have, 
regardless of what tricks and/or stratagems one uses. (I'm hoping it 
isn't true, since I have some environments where my named.conf has 5 
views defined in it, 2 of which are non-recursive, and another 1 of 
which sees an extremely small volume and diversity of queries, therefore 
it would be quite painful for the 2 remaining "real" recursive views to 
be limited to only 1/5th of the total memory space apiece).

                                     - Kevin

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