The Oracle Cloud Infrastructure Block Volume service provides you with the capability to group together multiple volumes in a volume group. A volume group can include both types of volumes, boot volumes, which are the system disks for your Compute instances, and block volumes for your data storage. You can use volume groups to create volume group backups and clones that are point-in-time and crash-consistent.
This simplifies the process to create time-consistent backups of running enterprise applications that span multiple storage volumes across multiple instances. You can then restore an entire group of volumes from a volume group backup.
To create a backup of the volume group
Open the navigation menu. Under Core Infrastructure, go to Block Storage and click Volumes Groups.
In the Volume Groups list, click Create Volume Group Backup in the Actions menu for the volume group you want to create a backup for.

Explanation
Remote VCN peering is the process of connecting two VCNs in different regions The peering allows the VCNs' resources to communicate using private IP addresses without routing the traffic over the internet or through your on-premises network.

Explanation
The File Storage service supports snapshots for data protection of your file system. Snapshots are a consistent, point-in-time view of your file systems. Snapshots are copy-on-write, and scoped to the entire file system. The File Storage service encrypts all file system and snapshot data at rest. You can take as many snapshots as you need.
Data usage is metered against differentiated snapshot data. If nothing has changed within the file system since the last snapshot was taken, the new snapshot does not consume more storage Snapshots are accessible under the root directory of the file system at .snapshot/name. For data protection, you can use a tool that supports NFSv3 to copy your data to a different availability domain, region, file system, object storage, or remote location.

Explanation
References:
The best practice for high availability and durability is to run the primary, standby, and observer in separate availability domains. The observer determines whether or not to failover to a specific target standby database
https://docs.cloud.oracle.com/en-us/iaas/Content/Database/Tasks/usingDG.htm#ConfiguringObserverOptional