In OCI, if you choose not to proactively reboot your instance before the scheduled maintenance due date, the system will handle the maintenance automatically to ensure that the instance remains operational.

Reboot-Migration or Rebuild in Place: If you don't reboot the instance yourself, OCI will automatically perform a reboot-migration or rebuild in place for the instance. This ensures that the instance is moved to new hardware or updated without your intervention, maintaining uptime and applying necessary updates or fixes.

Impact on Instance: The exact action taken (reboot-migration or rebuild in place) depends on the type of maintenance required. However, either action will temporarily interrupt the instance, typically involving a reboot, but the instance's data and configuration will be preserved.

Relevant OCI Documentation:

Instance Maintenance

OCI Maintenance Events

These references discuss the procedures and options available for handling instance maintenance in OCI.

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