[Pdns-users] Performance issues

[Martijn Reening]

> You do around 441 DNS queries/second. A single database connection
> would therefore not be able to support your needs (given DNSSEC).

We are currently running with 3 receiver-threads and 3
distributor-threads. We have tried every combination of 1, 3 and 4 of
each of these parameters without much effect. Running on a single
receiver-thread increases the latency with several milliseconds,
however, the problem seems harder to trigger. Having set the number of
signing-threads to 4 has increased overall performance, but did not have
any effect on the issue.

> Can you enable graphs as described on https://blog.powerdns.com/2014/
> 12/11/powerdns-graphing-as-a-service/ ? This will allow us to see what
> is going on.

They are added as `pdns.wns{1..3}`. It takes some time to get back to
steady-state behavior.

> dnsgram may also have written a file for you with dropped queries, can
> you check if anything shows up there?

The list contains mostly between 6 and 20 retries for somewhere around
16000 domains. Some other domains are between 60 and 120 retries, mostly
AAAA and one ANY. It does not hint in the direction of a specific domain
or query type.

On 24/07/2018 14:46, bert hubert wrote:
> On Tue, Jul 24, 2018 at 02:22:08PM +0200, Martijn Reening wrote:
>> We are running PowerDNS 4.1.3 and have tested against MySQL 5.1.73 en
>> PostgreSQL 10.4. It runs on CentOS 6.9, tested with both kernel versions
>> `2.6.32-696.20.1.el6.x86_64` and `4.15.13-x86_64-linode106`.
> Thanks!
> 
>>    1.32192 millisecond/lookup
>>    Retrieved 31554 records, did 10000 queries which should have no match
>>    Packet cache reports: 0 hits (should be 0) and 0 misses
> 
> You do around 441 DNS queries/second. A single database connection would
> therefore not be able to support your needs (given DNSSEC).
> 
> Can you enable graphs as described on https://blog.powerdns.com/2014/12/11/powerdns-graphing-as-a-service/
> ? This will allow us to see what is going on.
> 
>>    99.43% of questions answered within 32.00 msec (3.52%)
>>    99.52% of questions answered within 64.00 msec (0.09%)
>>    99.65% of questions answered within 256.00 msec (0.12%)
>>    99.86% of questions answered within 1024.00 msec (0.21%)
> 
> So when it works, it is great, it appears.
> 
> dnsgram may also have written a file for you with dropped queries, can you
> check if anything shows up there?
> 
> 	Bert
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-- 
Regards,

Martijn Reening