1.\" 2.\" Copyright (c) 2012 Microsoft Corp. 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.Dd September 10, 2013 27.Dt HYPER-V 4 28.Os 29.Sh NAME 30.Nm hv_storvsc 31.Nd Hyper-V Storage Virtual Service Consumer 32.Sh SYNOPSIS 33To compile this driver into the kernel, place the following lines in 34the system kernel configuration file: 35.Bd -ragged -offset indent 36.Cd "device hyperv" 37.Ed 38.Sh DESCRIPTION 39The 40.Nm 41driver implements the virtual store device for 42.Fx 43guest 44partitions running on Hyper-V. 45.Fx 46guest partitions running on Hyper-V do not have direct access to 47storage devices attached to the Hyper-V server. 48Although a 49.Fx 50guest can access storage devices using Hyper-V's 51full emulation mode, the performance in this mode tends to be unsatisfactory. 52.Pp 53To counter the above issues, the 54.Nm 55driver implements a storage 56Virtual 57Service Consumer (VSC) that relays storage requests from the guest partition 58to the storage Virtual Service Provider (VSP) hosted in the root partition 59using the high performance data exchange infrastructure provided by 60.Xr hv_vmbus 4 61driver. 62The VSP in the root partition then forwards the storage related requests to 63the physical storage device. 64.Pp 65This driver functions by presenting a SCSI HBA interface to the Comman Access 66Method (CAM) layer. 67CAM control blocks (CCBs) are 68converted into VSCSI protocol messages which are delivered to the root 69partition VSP over the Hyper-V VMBus. 70.Sh SEE ALSO 71.Xr hv_ata_pci_disengage 4 , 72.Xr hv_netvsc 4 , 73.Xr hv_utils 4 , 74.Xr hv_vmbus 4 75.Sh HISTORY 76Support for 77.Nm 78first appeared in 79.Fx 10.0 . 80The driver was developed through a joint effort between Citrix Incorporated, 81Microsoft Corporation, and Network Appliance Incorporated. 82.Sh AUTHORS 83.An -nosplit 84.Fx 85support for 86.Nm 87was first added by 88.An Microsoft BSD Integration Services Team Aq Mt bsdic@microsoft.com . 89