bind 9.6.2 with threads hangs

[Cathy Almond]

Fabien Seisen wrote:

> 
>> To the OP: do you specify max_cache_size? If not, what does the memory
>> consumption of BIND look like when it gets into the non-functional state?
>>
> 
> yes, max-cache-size 512M but named process takes ~900MB
> 

The extra memory is for keeping track of recursive clients (i.e.
in-progress client queries).

---

This doesn't sound like a hugely loaded server, else it's somewhat
throttled (not particularly large cache and probably default limit on
recursive clients).  What kind of query rates do you have?  Do you get
any logging that suggests resource problems?  If so, you might need to
increase some of the limits.

It's intriguing that you're seeing the same issues on two bind versions
and two OS (and that other people's experience is different from yours)
- it suggests to me that it's specific to your configuration or client
base/queries or your environment.

For troubleshooting I'd start by looking at the logging output - if
you've got any categories going to null, un-suppress them temporarily;
and add query-errors (see 9.6.2 ARM).  Then perhaps do some sampling of
network traffic (perhaps there's a UDP message size/fragmentation issue)
 to see what's happening (or not).