GNBD/VIA: a network block device over virtual interface architecture on Linux

This paper describes a design and implementation of GNBD/VIA, a network block device (NBD) over virtual interface architecture (VIA), and evaluates its performance on Linux-based cluster of PCs. VIA is a user-level memory-mapped communication model which provides zero-copy communication by removing the operating system from the critical communication path. Typically, an NBD layer offers the abstraction of a storage media across the network. GNBD/VIA attempts to improve the performance of the NBD layer by employing the lightweight VIA communication mechanisms between NBD servers and clients. To our best knowledge, GNBD/VIA is the first implementation of NBD on VIA. GNBD/VIA outperforms the normal NBD placed on top of TCP/IP protocol stacks, and achieves the performance comparable to local disk devices, showing the read (write) bandwidth of 30.6MB/s (25.9MB/s) on the evaluation platform with UDM.9100 hard disks and Emulex cLAN adapters.