BIND-9.16.1 memory leak?

Karl Pielorz kpielorz_lst at
Fri Apr 17 15:02:30 UTC 2020

--On 17 April 2020 at 15:45:16 +0200 sthaug at wrote:

> We have what appears to be a significant memory leak in BIND-9.16.1.
> Running a ps command for the named process every minute and logging
> the result, I see the named virtual memory size (VSZ) increasing at
> around 1.2 Mbyte/minute, and the resident size (RSS) increasing at
> around 0.85 Mbyte/minute. No problems due to this so far, but pretty
> obviously it's not viable in the long run.
> I tried reading the CHANGES from 9.16.2, and didn't see anything which
> suggested a fix for a memory leak problem.
> Any suggestions?


I seem to remember we got 'bitten' by large memory use when moving from a 
previous version of bind - do you have 'max-cache-size' set in your config?

As far as I can remember, the 'default' is to take 90% of the memory on the 
machine. This is great, unless the machine has lots of other stuff going on 
etc.  I think we noticed this during bind startup (i.e. from syslog output).

On our boxes we set it to "something sensible" - rather than using the 

Might not be your problem - but thought it was worth mentioning / checking.


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