The enterprise storage industry is witnessing a move from Network Attached Storage (NAS) solutions to high-performance Storage Area Networks (SAN). This transition is not easy because of the well-entrenched NAS infrastructure that has already been deployed. This paper attempts to define a file-system, DirectNFS, which can use existing NAS infrastructure with evolving SAN technology to provide the benefits of high-performance storage while reducing the cost of migration.
The proposed system presents a NAS interface to existing NAS clients while allowing DirectNFS clients to access storage directly over shared SAN. A server maintains the NAS interface for legacy clients and arbitrates access to metadata by DirectNFS clients, ensuring that the system is operable for both legacy NAS and DirectNFS clients. The communication protocol of DirectNFS is designed as an extension of traditional network file-system protocols.