> From: Hal Murray <[email protected]> > > [email protected] said: >> we set the speed to 25Mbps, so the ntp traffic is about 4939.8 packets/sec. >> the NTP server could not keep up requests, then the score is down. > > How did you get 4939.8? > Maybe ppyy just set up MRTG monitoring and read the results. I also set it up in my server.
> You can't predict the traffic load directly from the bandwidth you sign up > for. That's just a scale factor. If your system is overloaded, reduce the > bandwidth. > For a country with over 1 billion population and only *several* ntp pool servers available, I believe the load balancer can hardly work as intended. If available server count <= 4, then all servers will be provided to requesting clients, without regarding its registered bandwidth. And then servers with limited computing power/bandwidth will start dropping packets; when dropping probing packet from monitoring server, the score is dropped. If the score drops below 10, then the affected server becomes temporarily unavailable (even if the server itself running fine, just overloading), further burdening other surviving servers. Take my server in Taiwan (2 servers for 23 million population) for example. I only registered my server with least option: 384k, but constantly replying with about 6.5k packets/sec from 11am to 11pm everyday... Simple math shows you the limitation of current load balancing framework. > With ntpd, if you turn on sysstats, it will log the number of packets your > server has processed every hour. Look in monopt.html > > What sort of hardware was that running on? What was your ntp.conf? > The 6.5k packets/sec mentioned above is served with 15 yrs old Celeron 1G processor. Obviously my server is bottlenecked by its CPU, but I will not invest further. Recruiting more servers is a better solution. > I've seen over 10,000 packets per second on a Raspberry Pi 3. That's with > only 1 "client" generating traffic so it may be getting some unlikely cache > hits. Running top on the server slows things down, but I'm not sure why. > There are 4 CPUs. It also shows ntpd using all of one CPU. > Poor ntpd design not able to utilize muitl-core hardware. Great Raspberry Pi design to beat 15 yrs old desktop computer in single-core computing power. :) _______________________________________________ pool mailing list [email protected] http://lists.ntp.org/listinfo/pool
