6 ms·
Google has their own fleet of atomic clocks and time servers. So does AWS. So does Microsoft. So does Ubuntu. They're not going to drift enough for months to ca
by Animats 11mo ago
Google has their own fleet of atomic clocks and time servers. So does AWS. So does Microsoft. So does Ubuntu. They're not going to drift enough for months to cause trouble. So the Internet can ride through this, mostly.
The main problem will be services that assume at least one of the NIST time servers is up. Somewhere, there's going to be something that won't work right when all the NIST NTP servers are down. But what?
- adastra22 11mo agoI know this is HN, but the internet is pretty low on the list of things NIST time standards are important for.
- willis936 11mo agoBut pretty high on the list that NIST NTP is important for (since it leaves the building through the internet).
- adastra22 11mo agoIf NIST NTP goes down, the internet doesn’t go down. But atomic clocks drifting does upset many scientific experiments, which would effectively go down for the duration of the outage.
- willis936 11mo agoThis is the reason GP listed out all the alternative robust NTP services that are GPS disciplined, freely available, and used as redundant sources by any responsible timekeeper. What atomic clocks are disciplined by NTP anyway? Local GPS disciplining is the standard. If you're using NTP you don't need precision or accuracy in your timekeeping.
- szundi 11mo ago[dead]
- willis936 11mo agoAlso, I forgot to mention that NIST offers (and many institutions use) a service that provides a local rubidium reference that is GPS disciplined and they give you monthly reports that tell you the offset of the timestamps that were reported so they can be corrected. These services did not suffer interruptions.
- _zoltan_ 11mo agocould you list 3 things that you think are more important than the internet? (I know the internet is going to be fine; I just want to understand what you think ranks higher globally...)
- adastra22 11mo agoMostly scientific stuff like astronomical observations — e.g. did this event observed at one telescope coincide with neutrinos detected at this other observatory. Note I didn’t say they are more important than the Internet. That’s a value judgement in any case. I said that NIST level 0 NTp servers are more important to these use cases than they are to the Internet.
- misnome 11mo agoAll these use at least GPS for timing
- adastra22 11mo agoNo, they don’t. GPS is orders of magnitude less reliable than the most up to date metric time synchronization over fixed topology fiber links.
- misnome 11mo agoI wonder why we bothered building GPS signal waveguides into the bottom of a mine then. Clearly we should have consulted the experts of hacker news first. Losing NTP for a day is going to affect fuck-all.
- AlotOfReading 11mo agoI'm not even sure why you're trying to argue this. It's well established that Time over Fiber is 1-2 orders of magnitude more accurate and precise than GNSS time. Fiber time is also immune to many of the numerous sources of interference GNSS systems encounter, which anyone who's done serious timekeeping will be well acquainted with.
- 2snakes 11mo agoIn a past job I set up at least 5 domain dns servers pointing at nist ntp…
- genidoi 11mo agoAtomic clock non-expert here, what does having a fleet of atomic clocks entail and why would the hyperscalers bother?
- Gabrys1 11mo agoHaving clocks synchronized between your servers is extremely useful. For example, having a guarantee that the timestamp of arrival of a packet (measured by the clock on the destination) is ALWAYS bigger than the timestamp recorded by the sender is a huge win, especially for things like database scaling. For this though you need to go beyond NTP into PTP which is still usually based on GPS time and atomic clocks
- riedel 11mo agoActually interesting to think about what UTC actually means and there is seems to be no absolute source of truth [0]. I guess the worry is not that much about the NTP servers (for which people anyways should configure fail overs) but the clocks themselves. [0] https://www.septentrio.com/en/learn-more/insights/how-gps-brings-time-world?utm_source=perplexity https://www.septentrio.com/en/learn-more/insights/how-gps-br...
- pbhjpbhj 11mo agoCould you define an absolute source of truth based on extrinsic features. Something like taking an intrinsic time from atomic sources, pegged to an astronomic or celestial event; then a predicted astronomic event that would allow us to reconcile time in the future. It might be difficult to generate enough resolution in measurable events that we can predict accurately enough? Like, I'm guessing the start of a transit or alignment event? Maybe something like predicting the time at which a laser pulse will be returnable from a lunar reflector -- if we can do the prediction accurately enough then we can re-establish time back to the current fixed scale. I think I'm addressing an event that won't ever happen (all precise and accurate time sources are lost/perturbed), and if it does it won't be important to re-sync in this way. But you know...
- 11mo ago
- guenthert 11mo agoUbuntu using atomic clocks would surprise me. Sure they could, but it's not obvious to me why they would spend $$$$ on such. More plausible to me seems that they would be using GPSDO as reference clocks (in this context, about as good as your own atomic clock), iff they were running their own time servers. Google finds only that they are using servers from the NTP Pool Project, which will be using a variety of reference clocks. If you have information on what they actually are using internally, please share.
- puzzlingcaptcha 11mo agoI think people have a wrong idea of what a modern atomic clock looks like. These are readily available commercially, Microchip for example will happily sell you hydrogen, cesium or rubidium atomic clocks. Hydrogen masers are rather unwieldy, but you can get a rubidium clock in a 1U format and cesium ones are not much bigger. I think their cesium freq standards are formerly a HP business they acquired. Example: https://www.microchip.com/en-us/products/clock-and-timing/components/atomic-clocks/atomic-system-clocks/cesium-time/4310b https://www.microchip.com/en-us/products/clock-and-timing/co...
- xorcist 11mo agoIt is also important to realize that an atomic clock will only give you a steady pulse. It will count seconds for you, and do so very accurately, but that is not the same as knowing what time it is. If you get a rubidium clock for your garage, you can sync it up with GPS to get an accurate-enough clock for your hobby NTP project, but large research institutions and their expensive contraptions are more elaborate to set up.
- badmonkey0001 11mo agoThere are dedicated turnkey vendors these days, so there's no need to get elaborate. All you need is a U of rack or two and enough cash. Example: https://www.accubeat.com/ntp-ptp-time-servers https://www.accubeat.com/ntp-ptp-time-servers
- 11mo ago
- axlee 11mo agoCan't they point these dns records to working servers meanwhile to avoid degradation?
- creatonez 11mo agoMy understanding is that people who connect specifically to the NIST ensemble in Boulder (often via a direct fiber hookup rather than using the internet) are doing so because they are running a scientific experiment that relies on that specific clock. When your use case is sensitive enough, it's not directly interchangable with other clocks. Everyone else is already connecting to load balanced services that rotate through many servers, or have set up their own load balancing / fallbacks. The mistakenly hardcoded configurations should probably be shaken loose anyways.
- toast0 11mo agoIf you use a general purpose hostname like time.nist.gov: that should resolve to an operational server and it makes sense to adjust during an incident. If you use a specific server hostname like time-a-b.nist.gov: that should resolve to the specific server and you're expected to have multiple hosts specified; it doesn't make sense to adjust during an incident, IMHO. You wanted boulder, you're getting boulder, faults and all.
- dredmorbius 11mo agoGPS?