Operation Manual
17
Time Synchronization with
NTP
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.
Maintaining an exact system time is important in many situations. The built-in hardware
(BIOS) clock does often not meet the requirements of applications such as databases
or clusters. Manual correction of the system time would lead to severe problems because,
for example, a backward leap can cause malfunction of critical applications. Within a
network, it is usually necessary to synchronize the system time of all machines, but
manual time adjustment is a bad approach. NTP provides a mechanism to solve these
problems. The NTP service continuously adjusts the system time with the help of reliable
time servers in the network. It further enables the management of local reference clocks,
such as radio-controlled clocks.
17.1 Conguring an NTP Client with
YaST
The NTP daemon (ntpd) coming with the ntp package is preset to use the local
computer clock as a time reference. Using the (BIOS) clock, however, only serves as
a fallback for cases where no time source of better precision is available. YaST facilitates
the conguration of an NTP client.
Time Synchronization with NTP 323