The explanation is that the Infrequent Access tier is suitable for storing data that is accessed less frequently but requires immediate access when needed. The Infrequent Access tier has lower storage costs than the Standard tier, but higher retrieval costs. The Infrequent Access tier also has a minimum storage duration of 30 days, which means that you will be charged for at least 30 days of storage even if you delete or move the data before that period.

The explanation is that shielded instances are VM instances that have additional security features to protect them from low-level threats, such as rootkits and bootkits that can infect the firmware and operating system and are difficult to detect. Shielded instances use verified boot, which ensures that only trusted software components are executed during the boot process. Shielded instances also use virtual trusted platform module (vTPM), which provides a secure storage for encryption keys and certificates. Shielded instances are available for Oracle Linux 8 platform images with VM.Standard2.* shapes.

Ensure VCN CIDR prefix overlaps with other VCNs in your tenancy or with your organizations private IP network ranges. The explanation is that a VCN CIDR prefix is the range of IPv4 addresses that can be used within the VCN and its subnets. The VCN CIDR prefix should not overlap with other VCNs in your tenancy or with your organization’s private IP network ranges, as this can cause routing conflicts and connectivity issues. You should choose a VCN CIDR prefix that is large enough to accommodate your current and future needs, but not too large to waste IP addresses. You can use any of the private IPv4 address ranges specified in RFC 1918 for your VCN CIDR prefix.