2015-01-27 6:59 GMT-03:00 bert hubert <bert.hub...@powerdns.com>: > On Sun, Jan 25, 2015 at 10:33:34AM -0300, Ciro Iriarte wrote: > > Also, the test traffic was stopped, so the trace file should be complete > > and cleaner!. > > Ciro, > > I don't see anything that is wrong here. From a cold cache, it takes 11 > queries to resolve 2.centos.pool.ntp.org. > > Your network used up the following amounts of time on those queries: > in 266ms > in 226ms > in 184ms > in 226ms > in 233ms > in 267ms > in 223ms > in 201ms > in 224ms > in 51ms > in 199ms > > Which together is around 2 seconds. > > If there is a problem, the problem is that your network is pretty far away > from most servers it appears. > > If you redo your query with the latest PowerDNS test version (3.7.0-RC1) > you'll get slightly better timing output with --trace, which perhaps could > tell you a little more. > > On a high-latency network (and your fastest response to anything in this > trace was 51ms, even if I look at the other queries too), having a warm > cache is super important. > > Good luck! > > Bert >
Hi Bert, thanks for the analysis!. I double checked all the configuration (routing/pdns/linux) and everything seems to be OK. It's obviously not a PDNS thing as a trace using dig still gives pretty bad times ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.30.rc1.el6 <<>> +trace 2.centos.pool.ntp.org ;; Received 241 bytes from 186.16.16.16#53(186.16.16.16) in 1317 ms <--- this goes to localhost for recursion ;; Received 441 bytes from 199.7.83.42#53(199.7.83.42) in 5628 ms ;; Received 153 bytes from 199.19.57.1#53(199.19.57.1) in 2881 ms ;; Received 189 bytes from 128.175.13.17#53(128.175.13.17) in 8346 ms ;; Received 187 bytes from 94.242.223.210#53(94.242.223.210) in 644 ms Complete trace: http://pastebin.com/tvKqhq2e What I find weird is that a query to the server 199.7.83.42 takes more than 5 seconds, but a plain ping request gives a RTT of about 177ms. Maybe the servers are overloaded and I'm over-reacting :P --- 199.7.83.42 ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4187ms *rtt min/avg/max/mdev = 177.556/178.459/181.044/1.334 ms* The same goes for the other destinations: --- 199.19.57.1 ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4183ms *rtt min/avg/max/mdev = 177.125/177.302/177.644/0.565 ms* --- 128.175.13.17 ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4194ms *rtt min/avg/max/mdev = 187.530/188.211/189.673/0.931 ms* --- 94.242.223.210 ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4276ms *rtt min/avg/max/mdev = 265.467/269.252/272.820/2.637 ms* The only other thing I could think of is some kind of QoS issue and to blame the carrier. It's time to poke the networking guys... Regards, -- Ciro Iriarte http://iriarte.it --
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