Reference:https://oracle.github.io/learning-library/oci-library/L100-LAB/Autonomous_Data_Warehouse/ADW_

Explanation
A load balancer improves resource utilization, facilitates scaling, and helps ensure high availability. You can configure multiple load balancing policies and application-specific health checks to ensure that the load balancer directs traffic only to healthy instances. The load balancer can reduce your maintenance window by draining traffic from an unhealthy application server before you remove it from service for maintenance.
The Load Balancing service considers a server marked drain availablefor existing persisted sessions. New requests that are not part of an existing persisted session are not sent to that server.
Edit Drain State: Opens a dialog box in which you can change the drain state.
If you set the server's drain status to true, the load balancer stops forwarding new TCP connections and new non-sticky HTTP requests to this backend server.
This setting allows an administrator to take the server out of rotation for maintenance purposes.
e. Edit Offline State: Opens a dialog box in whichyou can change the offline status.
If you set the server's offline status to true, the load balance forwards no ingress traffic to this backend server.

Reference:https://docs.cloud.oracle.com/en-us/iaas/Content/Audit/Reference/logeventreference.htm#payload

Explanation
"You can add secondary VNICs to an instanceafter it's launched. Each secondary VNIC can be in a subnet in the same VCN as the primary VNIC, or in a different subnet that is either in the same VCN or a different one. However, all the VNICs must be in the same availability domain as the instance."
https://docs.cloud.oracle.com/en-us/iaas/Content/Network/Tasks/managingVNICs.htm