A system integrates an intelligent storage switch with a flexible virtualization system to enable the intelligent storage switch to provide efficient service of file and block protocol data access requests for information stored on the system. A storage operating system executing on a storage system coupled to the switch implements the virtualization system to provide a unified view of storage to clients by logically organizing the information as named files, directories and logical unit numbers. The virtualization system may be embodied as a file system having a write allocator configured to provide a flexible block numbering policy to the storage switch that addresses volume management capabilities, such as storage virtualization.