7 **qemu-storage-daemon** [options]
12 qemu-storage-daemon provides disk image functionality from QEMU, qemu-img, and
13 qemu-nbd in a long-running process controlled via QMP commands without running
14 a virtual machine. It can export disk images, run block job operations, and
15 perform other disk-related operations. The daemon is controlled via a QMP
16 monitor and initial configuration from the command-line.
18 The daemon offers the following subset of QEMU features:
29 Commands can be sent over a QEMU Monitor Protocol (QMP) connection. See the
30 :manpage:`qemu-storage-daemon-qmp-ref(7)` manual page for a description of the
33 The daemon runs until it is stopped using the ``quit`` QMP command or
34 SIGINT/SIGHUP/SIGTERM.
36 **Warning:** Never modify images in use by a running virtual machine or any
37 other process; this may destroy the image. Also, be aware that querying an
38 image that is being modified by another process may encounter inconsistent
44 .. program:: qemu-storage-daemon
48 .. option:: -h, --help
52 .. option:: -V, --version
54 Display version information and exit
56 .. option:: -T, --trace [[enable=]PATTERN][,events=FILE][,file=FILE]
58 .. include:: ../qemu-option-trace.rst.inc
60 .. option:: --blockdev BLOCKDEVDEF
62 is a block node definition. See the :manpage:`qemu(1)` manual page for a
63 description of block node properties and the :manpage:`qemu-block-drivers(7)`
64 manual page for a description of driver-specific parameters.
66 .. option:: --chardev CHARDEVDEF
68 is a character device definition. See the :manpage:`qemu(1)` manual page for
69 a description of character device properties. A common character device
70 definition configures a UNIX domain socket::
72 --chardev socket,id=char1,path=/tmp/qmp.sock,server,nowait
74 .. option:: --export [type=]nbd,id=<id>,node-name=<node-name>[,name=<export-name>][,writable=on|off][,bitmap=<name>]
75 --export [type=]vhost-user-blk,id=<id>,node-name=<node-name>,addr.type=unix,addr.path=<socket-path>[,writable=on|off][,logical-block-size=<block-size>][,num-queues=<num-queues>]
76 --export [type=]vhost-user-blk,id=<id>,node-name=<node-name>,addr.type=fd,addr.str=<fd>[,writable=on|off][,logical-block-size=<block-size>][,num-queues=<num-queues>]
78 is a block export definition. ``node-name`` is the block node that should be
79 exported. ``writable`` determines whether or not the export allows write
80 requests for modifying data (the default is off).
82 The ``nbd`` export type requires ``--nbd-server`` (see below). ``name`` is
83 the NBD export name. ``bitmap`` is the name of a dirty bitmap reachable from
84 the block node, so the NBD client can use NBD_OPT_SET_META_CONTEXT with the
85 metadata context name "qemu:dirty-bitmap:BITMAP" to inspect the bitmap.
87 The ``vhost-user-blk`` export type takes a vhost-user socket address on which
88 it accept incoming connections. Both
89 ``addr.type=unix,addr.path=<socket-path>`` for UNIX domain sockets and
90 ``addr.type=fd,addr.str=<fd>`` for file descriptor passing are supported.
91 ``logical-block-size`` sets the logical block size in bytes (the default is
92 512). ``num-queues`` sets the number of virtqueues (the default is 1).
94 .. option:: --monitor MONITORDEF
96 is a QMP monitor definition. See the :manpage:`qemu(1)` manual page for
97 a description of QMP monitor properties. A common QMP monitor definition
98 configures a monitor on character device ``char1``::
100 --monitor chardev=char1
102 .. option:: --nbd-server addr.type=inet,addr.host=<host>,addr.port=<port>[,tls-creds=<id>][,tls-authz=<id>][,max-connections=<n>]
103 --nbd-server addr.type=unix,addr.path=<path>[,tls-creds=<id>][,tls-authz=<id>][,max-connections=<n>]
105 is a server for NBD exports. Both TCP and UNIX domain sockets are supported.
106 TLS encryption can be configured using ``--object`` tls-creds-* and authz-*
109 To configure an NBD server on UNIX domain socket path ``/tmp/nbd.sock``::
111 --nbd-server addr.type=unix,addr.path=/tmp/nbd.sock
113 .. option:: --object help
115 --object <type>[,<property>=<value>...]
117 is a QEMU user creatable object definition. List object types with ``help``.
118 List object properties with ``<type>,help``. See the :manpage:`qemu(1)`
119 manual page for a description of the object properties.
123 Launch the daemon with QMP monitor socket ``qmp.sock`` so clients can execute
126 $ qemu-storage-daemon \
127 --chardev socket,path=qmp.sock,server,nowait,id=char1 \
128 --monitor chardev=char1
130 Export raw image file ``disk.img`` over NBD UNIX domain socket ``nbd.sock``::
132 $ qemu-storage-daemon \
133 --blockdev driver=file,node-name=disk,filename=disk.img \
134 --nbd-server addr.type=unix,addr.path=nbd.sock \
135 --export type=nbd,id=export,node-name=disk,writable=on
137 Export a qcow2 image file ``disk.qcow2`` as a vhosts-user-blk device over UNIX
138 domain socket ``vhost-user-blk.sock``::
140 $ qemu-storage-daemon \
141 --blockdev driver=file,node-name=file,filename=disk.qcow2 \
142 --blockdev driver=qcow2,node-name=qcow2,file=file \
143 --export type=vhost-user-blk,id=export,addr.type=unix,addr.path=vhost-user-blk.sock,node-name=qcow2
148 :manpage:`qemu(1)`, :manpage:`qemu-block-drivers(7)`, :manpage:`qemu-storage-daemon-qmp-ref(7)`