Even if nothing has changed within the file system since the last snapshot was taken, a new snapshot does not consume more storage. This is because snapshots are incremental and only store the changes made to the file system since the previous snapshot. The other statements are correct regarding the OCI File System snapshots. Reference: [Snapshots and Storage Consumption]

The explanation is that burstable instances are VM instances that have a baseline utilization of either 12% or 50% of each CPU core, not 25% or 75%. Burstable instances are designed for scenarios where an instance is typically idle or has low CPU utilization but occasionally needs to burst above the baseline to handle spikes in demand. Burstable instances cost less than regular instances with the same total OCPU count but charge extra for bursting above the baseline OCPU.

Export your current image in the QCOW2 format and copy to an Object Storage bucket. Import it as a custom image. Select emulated mode to ensure compatibility with legacy drivers. The explanation is that QCOW2 is one of the supported formats for importing custom images to OCI. Custom images are images that you can create from your own on-premises or cloud servers and use them to launch instances in OCI. To import a custom image, you need to export your current image in a supported format, copy it to an Object Storage bucket, and then import it as a custom image using the OCI console or API. When you import a custom image, you can choose between native mode or emulated mode. Native mode offers better performance but requires compatible drivers and firmware. Emulated mode offers better compatibility but lower performance.

By default, the primary VNIC of an instance in a subnet has one primary private IP address. A private IP can have an optional public IP assigned to it if it resides in a public subnet. The explanation is that a private IP address is an IPv4 address that is assigned to a VNIC and belongs to the CIDR block of the VCN or subnet. By default, the primary VNIC of an instance in a subnet has one primary private IP address, which is automatically assigned by OCI and cannot be changed. However, you can also assign secondary private IP addresses to a VNIC, either manually or automatically, up to a maximum of 31 per VNIC. A private IP address can have an optional public IP address assigned to it, which allows the instance to communicate with the internet. A public IP address can be either ephemeral or reserved, depending on whether you want to keep it after stopping or terminating the instance. A private IP address can only have a public IP address assigned to it if it resides in a public subnet, which means that the subnet's route table has a route rule that directs traffic to the internet gateway.

Oracle Security Zones is a service that helps you enforce best practices and prevent misconfigurations on your OCI resources by applying predefined policies and controls. Some of the benefits of using Security Zones are:

Encrypt storage resources with a customer-managed key: Security Zones require that all storage resources, such as block volumes, boot volumes, file systems, and object storage buckets, are encrypted with a customer-managed key from Vault. This ensures that you have full control over the encryption and decryption of your data at rest.

Deny public access to OCI resources, such as databases and object storage buckets: Security Zones prevent you from creating or updating OCI resources that have public access enabled, such as databases and object storage buckets that are accessible from the internet. This reduces the risk of unauthorized access or data leakage.