Data volume access protocol conversion without data copy

A computer system having a host computer coupled to a data storage system, the data storage system hosting a storage volume, the host computer and data storage system being configured and co-operative to perform a method of copy-free, non-disruptive conversion of the storage volume from a first access protocol to a distinct second access protocol, the method including:

• in a preparatory step in which the storage volume is identified as a source volume for protocol conversion, creating a destination volume accessible according to the second access protocol, the destination volume created in a storage-sharing domain of the source volume, the storage volume referencing underlying stored data;
• creating a pairing of a token and a handle, the token representing data content of the source volume, the handle being associated with the token and usable to represent the source volume according to the second protocol;
• in response to a subsequent copy-with-handle command including the handle, and based on the pairing of the handle with the token, populating metadata of the destination volume to reference, without copying, the underlying stored data, the destination volume thereafter functioning as the storage volume accessed using the second protocol.