I want to ask about this “io timeout” that appears on csv log, i see the pontuation droping and connection dropping. What should be done at the server side to skip this errors? I’m operator of a stratum 1 NTP server that is a Raspberry PI 3 without original crystal oscillator (19.2MHz), we has connected the crystal input at one DDS that is connected to a local time scale UTC(LRTE) and is traceable in BIPM time department: https://goo.gl/oSzRrF
Thanks for reply! I changed it to 10MB/s, here we have a bandwidth of 1GB/s, but raspberry ethernet only supports 10/100 connection (Pi 3B not plus), did you think is good keep this value (10mb/s) or i can incrase it to something near to 100mb/s?
The net speed is used to balance the load between the pool servers. If your connection is asymmetric (like most DSL connections) you should use the lower speed.
The amount of queries your server will get is generally directly proportional to the netspeed, so a 50Mbit setting will get about 5 times more traffic than the 10Mbit setting. The pool will only use a fraction of the “netspeed setting”. Be aware that the amount of queries to your server will grow over time.
Depending on which NTP program you use, there are commands to monitor performance and you can see if it’s dropping packets or if you are just experiencing a network issue between you & the monitoring server.
The program that does the monitoring is at https://github.com/ntppool/monitor - review and patches are welcome. The production system is configured to just do “one probe”. The old system did more (sorta).
I have been working on making the long term logs more useful (and accessible). In the process I noticed that the “worse monitoring” started around March last year (and not during the summer when various network changes were done, to my surprise).
It used to be that about 0.5% of the monitoring probes to servers that have recently worked would fail. This is still the case for IPv6, but for IPv4 servers it’s gone up to around 1%.
(I’ll most the queries and data in more detail later when I’m done with the data processing; the server doing it is using terabytes of (compressed) space temporarily, it’s pretty slow to work with).
Seems more stable now, i’ve dropped server speed configuration to 768kbit, this is a little shameful but it keeps server available. Also, tunned some parameters at sysctl in server side. Like:
i dont know if tcp_congestion_control changing makes a real effect at ntp, concerning this uses upt protocol. But, you guys have some another recommendation? The server is in one public university, that we have a real IP addres with full internet access, now i’m measuring a conntrack count of 220324 what is a huge value, stock is arround 65536… What did you think about?
very intersting, i will use this too for my openwrt rpi server in my home, as this rpi ntp server i only have 1gb of ram… And… in accordance with this logic, logging this can eat a lot of RAM!!