Explanation
NFS export options enable you to create more granular access control than is possible using just security list rules to limit VCN access. You can use NFS export options to specify access levels for IP addresses or CIDR blocks connecting to file systems through exports in a mount target. Access can be restricted so that each client's file system is inaccessible and invisible to the other, providing better security controls in multi-tenant environments.
Using NFS export option access controls, you can limit clients' ability to connect to the file system and view or write data. For example, if you want to allow clients to consume but not update resources in your file system, you can set access to Read Only. You can also reduce client root access to your file systems and map specified User IDs (UIDs) and Group IDs (GIDs) to an anonymous UID/GID of your choice. For more information about how NFS export options work with other security layers

Not all migration methods apply to all migration scenarios. Many of the migration methods apply only if specific characteristics of the source and destination databases match or are compatible. Moreover, additional factors can affect which method you choose for your migration from among the methods that are technically applicable to your migration scenario.
Some of the characteristics and factors to consider when choosing a migration method are:
On-premises database version
Database service database version
On-premises host operating system and version
On-premises database character set
Quantity of data, including indexes
Data types used in the on-premises database
Storage for data staging
Acceptable length of system outage
Network bandwidth

Explanation
STEERING POLICIES is A framework to define the traffic management behavior for your zones. Steering policies contain rules that help to intelligently serve DNS answers.
FAILOVER
Failover policies allow you to prioritize the order in which you want answers served in a policy (for example, Primary and Secondary). Oracle Cloud Infrastructure Health Checks are leveraged to determine the health of answers in the policy. If the Primary Answer is determined to be unhealthy, DNS traffic will automatically be steered to the Secondary Answer.
LOAD_BALANCE
Load Balancer policies allow distribution of traffic across multiple endpoints. Endpoints can be assigned equal weights to distribute traffic evenly across the endpoints or custom weights may be assigned for ratio load balancing. Oracle Cloud Infrastructure Health Checks are leveraged to determine the health of the endpoint. DNS traffic will be automatically distributed to the other endpoints, if an endpoint is determined to be unhealthy.
ROUTE_BY_GEO
Geolocation-based steering policies distribute DNS traffic to different endpoints based on the location of the end user. Customers can define geographic regions composed of originating continent, countries or states/provinces (North America) and define a separate endpoint or set of endpoints for each region.
ROUTE_BY_ASN
ASN-based steering policies enable you to steer DNS traffic based on Autonomous System Numbers (ASN).
DNS queries originating from a specific ASN or set of ASNs can be steered to a specified endpoint.
ROUTE_BY_IP
IP Prefix-based steering policies enable customers to steer DNS traffic based on the IP Prefix of the originating query.

Due to the network speed is not good enough and the connection is Intermittent due to the damages caused to the electrical grid Oracle offers offline data transfer solutions that let you migrate data to Oracle Cloud Infrastructure.
You have 2 Options of Data Transfer
DISK-BASED DATA TRANSFER
You send your data as files on encrypted commodity disk to an Oracle transfer site. Operators at the Oracle transfer site upload the files into your designated Object Storage bucket in your tenancy.
APPLIANCE-BASED DATA TRANSFER
you send your data as files on secure, high-capacity, Oracle-supplied storage appliances to an Oracle transfer site. Operators at the Oracle transfer site upload the data into your designated Object Storage bucket in your tenancy.