Dear hackers, > Though this provides a way for users to control values required for > conflict resolution, I prefer a simple approach at least for the first > version which is to document that users should ensure time > synchronization via NTP. Even Oracle mentions the same in their docs
I researched some cloud services and found that the time-sync services on the cloud are integrated with the NTP or PTP direct connection. This means that there are no specific APIs to synchronize the machine clock. Based on that, I also agree with the simple approach (just document). I feel the synchronization can be regarded as the low-layer task and can rely on the OS. The below part shows the status of cloud vendors and Oracle. ## AWS case AWS provides a "Time Sync Service" [1] that can be used via NTP. The source server is at 169.254.169.123; users can modify the configuration file to refer to it shown below. ``` server 169.254.169.123 prefer iburst ``` Or users can even directly connect to the local and accurate hardware clock. ## GCP case GCP compute engines must use an NTP server on the GCP cloud [2], located at metadata.google.internal, or other public NTP servers. The configuration will look like this: ``` server metadata.google.internal iburst ``` ## Oracle case Oracle RAC requires that all participants are well synchronized by NTP. Formally, it had an automatic synchronization feature called "Cluster Time Synchronization Service (CTSS)." It is de-supported in Oracle Database 23ai [3]. [1]: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/configure-ec2-ntp.html [2]: https://cloud.google.com/compute/docs/instances/configure-ntp [3]: https://docs.oracle.com/en/database/oracle/oracle-database/23/cwlin/server-configuration-checklist-for-oracle-grid-infrastructure.html Best regards, Hayato Kuroda FUJITSU LIMITED
