Recursive bind becomes unresponsive with high load

[John Miller]

On Thu, Mar 31, 2016 at 2:00 PM, Michael Brunnbauer <brunni at netestate.de> wrote:
>
> hi all,
>
> On Thu, Mar 31, 2016 at 07:32:21PM +0200, Michael Brunnbauer wrote:
>> Is is possible that is this connected to rndc stats? I will stop doing
>> rndc stats for a while to test (it currently runs every minute).
>
> Not doing rndc stats did not prevent the problem. Any other ideas?

Hi Michael,

Are you doing query logging on this box? If so, you might check for
messages such as:

named[743]: clients-per-query decreased to 17

I know you tried setting max-clients-per-query earlier, but since this
is for a locally-hosted zone, query volume could be quite high
somewhere along the way.  Likewise, you might run

rndc status

and see what you get.

Something else you might try: if you don't already, turn on
server-statistics/statistics-channels:

https://kb.isc.org/article/AA-00769/0/Using-BINDs-XML-statistics-channels.html

You may get what you're looking for; you may not.

John