3 ms·
Take a look at Spanner paper for details. There’s a set of time master machines per datacenter that have GPS receivers attached, and a set of “Armageddon master
by packetslave 9y ago
Take a look at Spanner paper for details. There’s a set of time master machines per datacenter that have GPS receivers attached, and a set of “Armageddon masters” that have atomic clocks attached. Regular machines (including the Spanner servers) run a time slave daemon that talks to the master machines.
- sleavey 9y agoNaively I'd assume that the improvement in time accuracy GPS clocks provide must be greater than the harmful effect on accuracy created by network latency, even within data centres: you can't guarantee that a packet will arrive on time, since switches can, I believe as part of their protocol, apply a random wait to a packet. I assume there must be some special method to maintain a synchronous connection to the clock on each server over the network. Could it be as simple as some QoS rules in the switches for NTP packets?