3 ms·
What is TrueTime really? Are their Distributed Systems 'sharing a global clock'?
by pagade 10y ago
What is TrueTime really? Are their Distributed Systems 'sharing a global clock'?
- amaks 10y agoHere is a good article: http://www.bluetreble.com/2015/10/time-travel/ http://www.bluetreble.com/2015/10/time-travel/
- philip1209 10y agoFrom the Spanner paper: > The underlying time references used by TrueTime are GPS and atomic clocks. TrueTime uses two forms of time reference because they have different failure modes... TrueTime is implemented by a set of time master machines per datacenter and a timeslave daemon per machine. The majority of masters have GPS receivers with dedicated antennas; these masters are separated physically to reduce the effects of [GPS] antenna failures, radio interference, and spoofing. The remaining masters (which we refer to as Armageddon masters) are equipped with atomic clocks. An atomic clock is not that expensive: the cost of an Armageddon master is of the same order as that of a GPS master. Source: https://static.googleusercontent.com/media/research.google.com/en//pubs/archive/39966.pdf https://static.googleusercontent.com/media/research.google.c...
- fintler 10y agoHere's a very rough (and non-practical due to the large time error) implementation of TrueTime that I wrote a while back that uses the regular linux apis: https://stackoverflow.com/questions/18384883/why-is-googles-truetime-api-hard-to-duplicate https://stackoverflow.com/questions/18384883/why-is-googles-... I suppose if you spent some serious effort with ntpd (maybe hook it up to a PCI ClockCard), you could get this approach to work.