You can configure a NTP pool, which will request date and time from several NTP servers. In fact, that is the default configuration.
CLI
[admin@nodegrid date_and_time]# show /settings/date_and_time/
system time: Wed Jan 25 12:59:46 EST 2017
date_and_time = network_time_protocol
last_update: Wed Jan 25 12:59:10 2017 (24.248.217.23)
server = pool.ntp.org
zone = us|eastern
Web
System, Date and Time page:
| Date and Time: |
| ||||||||||
To check the NTP servers you can run the commands (as root)
chronyc -n tracking or chronyc -n sources