NTP Server is recommended for HANA System
What is NTP SERVER ?
The NTP (network time protocol) mechanism is a protocol for synchronizing the system time over the network. First, a machine can obtain the time from a server that is a reliable time source. Second, a machine can itself act as a time source for other computers in the network. The goal is twofold—maintaining the absolute time and synchronizing the system time of all machines within a network.
Virtual Machine Clock Synchronization Using NTP : https://blogs.sap.com/2019/02/25/virtual-machine-clock-synchronization-using-ntp/
SUSE Link for NTP Server :- https://documentation.suse.com/sles/15-SP1/html/SLES-all/cha-ntp.html