What is a criterion for storage-volume expansion?

The correct choice is that the virtual volume is mapped to the storage volume in a 1:1 configuration. This is significant because it means that for expansion to occur, each virtual volume must correspond directly to one storage volume. This one-to-one mapping is crucial as it simplifies the management of resources, ensuring that each virtual volume can effectively utilize the storage capacity it’s mapped to without confusion or overlap with other volumes.

In a storage environment, maintaining a structured and clear mapping between virtual and storage volumes is essential for performance and operational efficiency. It allows administrators to closely monitor and manage the resources being utilized and makes it easier to perform tasks like expansion without running into conflicts or performance issues.

While other choices may present valid scenarios for certain operations or characteristics of volume management, they do not directly pertain to the criteria needed specifically for the expansion of storage volumes. For instance, needing to be offline during expansion could introduce unnecessary downtime and may not be a requirement for all storage solutions, especially those designed to facilitate live operations. Similarly, the options regarding host assignments and volume sizes deal more with configuration management rather than the specific process of expanding storage volumes.