This article's purpose is to shed some light on the rarely discussed, yet a crucial alert that you may come across on the cluster, that is, the HardwareClockFailure alert.

Let us not confuse it with the system time. The system time is maintained by the OS (For example, Linux, Microsoft Windows etc.). The initial value of the system clock is typically retrieved from the real-time clock at power up or is set by the user. The hardware time is maintained by a real clock powered by a battery, which means it will persist a reboot. 

The alert is generated when the hardware clock time differs from the system clock time. This check is scheduled to run every 10 minutes, by default.

To learn more about what causes a hardware clock to fail and how to resolve it, head over to this KB article: KB 4120 in the Nutanix Support Portal.