" For those who manage large repositories of large files shared by a large number of users, scale-out NAS storage built on RAID arrays has been the go-to technology for years. But when the storage demand scales toward and beyond the petabyte level, a new architecture is needed for disk-based archives, one with extreme scalability and durability that reduces both capital and operating expenses. That new architecture is wide area storage.

Wide area storage combines next generation dispersed object storage with file system technologies in a new approach to archiving that overcomes these limitations and inefficiencies. Data repositories built on wide area storage are extremely scalable, durable and easy to maintain--allowing data to be stored forever on disk without business-halting service interruptions or painful data migrations."

http://www.datacenterpost.com/2012/11/beyond-raid-wide-area-...

Praticamente quasi tutti i risultati fanno riferimento al lancio di soluzioni di "wide area storage" da parte di Quantum e sono datati novembre 2012.
Presumo quindi che si tratti di una tecnologia piuttosto recente.
Lascerei il termine in inglese, così come solitamente avviene per "Wide Area Network (WAN)" oppure al massimo userei "storage/archiviazione wide area".