1.\" Copyright (c) 2016 Microsoft Corp. 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.Dd October 12, 2016 27.Dt HV_VSS_DAEMON 8 28.Os 29.Sh NAME 30.Nm hv_vss_daemon 31.Nd Hyper-V Volume Shadow Copy Service Daemon 32.Sh SYNOPSIS 33.Nm 34.Op Fl dn 35.Sh DESCRIPTION 36The 37.Nm 38daemon provides the ability to freeze and thaw the file system for 39.Fx 40guest partitions running on Hyper-V. 41.Pp 42Hyper-V allows administrators to backup or restore the 43.Fx 44guest partition. 45Administrators can 46use Windows Powershell scripts to backup or restore the 47.Fx 48VM. 49.Pp 50The 51.Nm 52accepts file system freeze and thaw requests from the 53.Xr hv_utils 4 54driver and performs the actual file-system operation. 55.Pp 56The file system freeze and thaw functionality is 57useful when the Hyper-V host wants to do live backup of 58.Fx 59guest. Hyper-V host sends file system freezing request to 60.Nm 61which conducts the real operation. After successfully freezing file 62system, Hyper-V host takes a snapshot of the VM. In the future, 63Hyper-V host can restore the 64.Fx 65VM through that snapshot. 66.Pp 67The options are as follows: 68.Bl -tag -width indent 69.It Fl d 70Run as regular process instead of a daemon for debugging purpose. 71.It Fl n 72Generate debugging output. 73.El 74.Sh SEE ALSO 75.Xr hv_vmbus 4 , 76.Xr hv_utils 4 , 77.Xr hv_netvsc 4 , 78.Xr hv_storvsc 4 , 79.Xr hv_kvp 4 80.Sh HISTORY 81The daemon was introduced in October 2016 and developed by Microsoft Corp. 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