Re: dnsdist and udp-in-errors

Remi Gacogne via Pdns-users <[email protected]> Thu, 14 Nov 2024 10:24:09 +0100

Newsgroups	gmane.network.dns.powerdns.user
Message-ID	<[email protected]>

Hi,

On 12/11/2024 17:15, janasowieso Nicht via Pdns-users wrote:
> ... of course, please find the output of dumpStats() below,
> in our statistics/graphs we couldn't detect anything strange or 
> noticeable, except the udp inerrors or "udp-in-errors".

OK, at this point I would recommend:

- lowering the amount of "addLocal" directives. I usually recommend 
having setting it to roughly half the number of cores dedicated to 
dnsdist, the other half going to the 'newServer' threads
- looking at why you are getting UDP checksum errors, as if I'm not 
mistaken you are getting a lot of these which doesn't look good
- checking if the CPU cores are not over-committed in the hypervisor, 
and ideally not crossing NUMA boundaries. The CPU steal metric looks OK, 
but still it makes no sense to be dropping so many UDP datagrams at such 
a low QPS rate. It looks like you are even dropping TCP connections 
(tcp-listen-overflows) which makes no sense either.

Hope that helps,
-- 
Remi Gacogne
PowerDNS.COM BV - https://www.powerdns.com/

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