Databento NTP service

Network Time Protocol (NTP) is an internet protocol commonly used to synchronize time between computer systems over a network. The Databento NTP service is a free public time service, based on NTP, that's available to everyone over internet and public cloud.

Who should use this

Databento's NTP service is ideal for financial users using proximity hosting services and public cloud providers like AWS, Azure, and GCP, and for users whose servers are located in the Chicago, New York, and New Jersey metro regions. While more accurate time synchronization practices exist for these users, the next marginal improvement for these users over our NTP service will require dedicated hosting or cross-connects, which are significantly more costly.

All live data users connecting to Databento over internet are strongly recommended to use this time service to ensure that their local system clock is synchronized against Databento's internal time source and that latency estimates taken between local timestamps and Databento timestamps are more accurate.

Getting started

Anyone can synchronize their clocks against our time service by pointing their NTP client at ntp.databento.com.

Alternatively, you can pick specific servers from this pool, as follows:

Recommended configuration

Here are some recommendations for obtaining good accuracy on your system clock against our NTP service:

• Use a high quality NTP client implementation, such as chrony.
• In most cases, you should only step the clock in the first few updates, before your application starts. You can configure this with the makestep directive in your chrony configuration:

makestep 1 3 

• Ensure your system clock is only adjusted by slewing while your application is running. This means that your clock is adjusted by slowing down or speeding up instead of stepping, which ensures monotonic timestamps. By default, chrony adjusts the clock by slewing.
• However, if your system does not have a real-time clock or is a virtual machine which can be suspended and resumed with an incorrect time, it may be necessary to allow stepping on every clock update, as follows:

makestep 1 -1 

In summary, you can add the following lines to your chrony configuration file, found at /etc/chrony.conf or /etc/chrony/chrony.conf:

pool ntp.databento.com iburst minpoll 4 maxpoll 4 # Step the system clock instead of slewing it if the adjustment is larger than # one second, but only in the first three clock updates makestep 1 3 

You can check that chrony is now using your new NTP sources with the chronyc sources command.

Architecture - How it works

Since the margin of error in time synchronization is largely a function of distance and hops to the time source, Databento's NTP service leverages our network of colocated servers at various financial data centers to help users obtain more accurate time.

The Databento NTP service is composed of a pool of stratum 1 NTP servers at the CyrusOne Aurora I and Equinix NY4 data centers. In contrast, common time providers usually situate their time servers in general-purpose data centers that are further from popular colocation and proximity hosting sites used by financial firms.

Another important reason to use Databento's time service is the nature of its clock source. The time servers for our service are synchronized against the same PTP time source used for supplemental receive and outbound timestamps in our data, thus our time servers have a margin of error under 200 nanoseconds:

MS Name/IP address Stratum Poll Reach LastRx Last sample =============================================================================== #* PTP 0 0 377 1 +9ns[ +11ns] +/- 159ns 

In turn, our PTP source is based on a pair of grandmaster clocks with under 25 nanosecond root-mean-squared error against UTC. Other public NTP services do not provide any guarantees about the quality of their clock sources—even if you were to obtain a time sync to their NTP servers with sub-millisecond tolerance, you may still be off from UTC by tens of milliseconds.