When consolidating snapshots, the data from the snapshot files is merged back into the original virtual disk. This process temporarily increases the disk space usage on the datastore because of the additional space required to merge the snapshot data into the primary disk.

Role-Based Access Control (RBAC) in vCenter is used to define and manage user roles and permissions. It allows administrators to control who can access specific resources and perform actions within the vCenter environment. RBAC ensures that users only have access to the areas and tasks they are authorized to interact with, enhancing security and management.

Lockdown Mode (A) restricts access, isolating the management network (C) protects host connectivity, and disabling SSH when not needed (D) reduces attack surfaces. Granting Administrator rights universally (B) is contrary to best practices.

Checking logs (A), ensuring correct firewall rules (B), and verifying DNS resolution (D) are key. Deleting and recreating the cluster (C) is rarely the first step and may cause more disruption.

The primary purpose of configuring a Key Management Server (KMS) in vCenter for VM Encryption is to manage and store the encryption keys that are used to secure virtual machine data. The KMS ensures that encryption keys are handled securely and provides a central management point for encrypting VMs in a VMware environment.