Thanks Bert, You are 100% correct! I used grepq as you suggested and indeed I have queries which took over 100ms plus the small sample size explains this. Out of curiosity is there a more elegant way to extract queries using grepq for external requests? I did the following to exclude internal domains:
dnsdist -e "grepq('.')" | egrep -v '<internal domain>|<another internal domain>|arpa' Nigel. On 19 March 2018 at 11:39, bert hubert <bert.hub...@powerdns.com> wrote: > On Mon, Mar 19, 2018 at 11:30:08AM +0000, Nigel H wrote: > > I'm seeing a discrepancy when i run showServers() in dnsdist. Our > internal > > pool of dns servers appears correct and monitoring shows the odd spike in > > latency but our external pool (opendns) seems to just keep increasing in > > value. The documentation states its the latency for this servers in > > milliseconds but when I test using dig I'm seeing normal resolution times > > 1-8ms mostly but dnsdist reports latency like below (27ms). > > Hi Nigel, > > The likely reason for the increase is that opendns has only received 169 > and > 148 queries so far. This means the weighted average latency still includes > a lot of 0. > > Eventually, you should see the opendns latency plateau. > > With 'grepq()' you should be able to find the queries being sent to > opendns, > and how long dnsdist thought they were taking. > > You could then perhaps retry those queries with 'dig' to see how long they > take. 27ms is not unreasonable for mostly cache misses. > > > Can someone confirm its meaning? Is it an average latency based an > amount > > of queries to this server or is it the highest latency seen? Also does > > dnsdist incorporate the latency of the health check? > > The last part, no. First part, it is average. > > Bert >
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