2 Functional Description

The Virtual Storage protocols that are described in this document provide functionality that supports:

  • Allowing clients to open a virtual disk file on a remote server message block (SMB) share.

  • Reading, writing, or closing of a virtual disk file on a remote SMB share.

  • Allowing clients to close a virtual disk file on a remote SMB share.

  • Allowing multiple clients to open a shared virtual SCSI disk on a remote share.

  • Reading, writing, or closing shared virtual SCSI disk files on the target server.

  • Forwarding of raw SCSI commands and receipt of their results.

The following table describes the available methods of accessing the remote virtual disk, and the advantages and limitations of each.

Method of Accessing Remote Virtual Disk

Advantages

Limitations

Using Server Message Block (SMB) Protocol Version 3 (SMB3)

Uses commodity storage hardware

Single-user access

Using SMB3 when using the SMB2 Remote Direct Memory Access (RDMA) Transport Protocol (SMBDirect) as a transport

Leverages RDMA-capable networks for higher throughputs, lower latencies, and CPU utilization

Uses commodity storage hardware

Single-user access

Using the Remote Shared Virtual Disk Protocol (RSVD) on top of SMB3

Multi-user access

Uses commodity storage hardware

Secure access to files

Using RSVD on top of SMB3 when using SMBDirect as a transport

Multi-user access

Leverages RDMA-capable networks for higher throughputs, lower latencies, and CPU utilization

Uses commodity storage

Secure access to files

Requires specialized network adapter hardware

Using Internet SCSI (iSCSI) to access the remote virtual disk

Multi-user access

Uses commodity storage hardware