Setting Network Time Protocol for Cluster Time Synchronization

You can use operating system configured network time protocol (NTP) such as chronyd or ntpd for time synchronization.

Note:

Cluster Time Synchronization Service (CTSS) is desupported in Oracle Database 23ai.

To synchronize time between cluster member nodes, use either an operating system configured network time protocol such as ntp or chrony. To verify that you have network time synchronization configured, you can use the cluvfy comp clocksync -n allnodes command.

Oracle Clusterware requires the same time zone environment variable setting on all cluster nodes. During installation, the installation process picks up the time zone (TZ) environment variable setting of the Grid installation owner on the node where Oracle Universal Installer (OUI) runs, and uses that time zone value on all nodes as the default TZ environment variable setting for all processes managed by Oracle Clusterware. The time zone default is used for databases, Oracle ASM, and any other managed processes. You can ensure time synchronization using an operating system configured network time protocol (NTP) such as chronyd or ntpd.

Note:

Before starting the installation of Oracle Grid Infrastructure, Oracle recommends that you ensure the clocks on all nodes are set to the same time.

Deactivating the NTP Service

To deactivate the Network Time Protocol (NTP) service, you must stop the ntpd and chronyd services, and disable them from the initialization sequences.

Complete these steps on Oracle Linux 8 and Red Hat Enterprise Linux 8:

Run the following commands as the root user to stop the ntpd service:
```
# systemctl stop ntpd
# systemctl disable ntpd
```
Rename the NTP-related configuration files in the /etc directory.
Run the following commands as the root user to stop the chronyd service:
```
# systemctl stop chronyd
# systemctl disable chronyd
```
Remove the chronyd service configuration file.

Parent topic: Configuring Operating Systems for Oracle Grid Infrastructure on Linux