Migrating a traditional volume to a virtual volume in a storage system

A system comprising:

• a file system to maintain a hierarchical structure of data stored in an array of physical storage devices and to service read and write requests from one or more clients relating to data stored in the array of physical storage devices;
• a traditional volume having one or more traditional volume index nodes, wherein each traditional volume index node is to provide physical address information relating to data stored in the array of physical storage devices;
• and
• a migration module to migrate the traditional volume to a virtual volume, wherein the virtual volume is to include one or more virtual volume index nodes to provide both physical address information and virtual address information relating to data stored in the array of physical storage devices.

An article of manufacture comprising:

• an electronically accessible medium providing instructions that, when executed by an apparatus, cause the apparatus to
• select a traditional volume index node;
• and
• convert the traditional volume index node to a virtual volume index node, wherein the virtual volume index node includes physical address information and virtual address information.