1QEMU Storage Daemon 2=================== 3 4Synopsis 5-------- 6 7**qemu-storage-daemon** [options] 8 9Description 10----------- 11 12qemu-storage-daemon provides disk image functionality from QEMU, qemu-img, and 13qemu-nbd in a long-running process controlled via QMP commands without running 14a virtual machine. It can export disk images, run block job operations, and 15perform other disk-related operations. The daemon is controlled via a QMP 16monitor and initial configuration from the command-line. 17 18The daemon offers the following subset of QEMU features: 19 20* Block nodes 21* Block jobs 22* Block exports 23* Throttle groups 24* Character devices 25* Crypto and secrets 26* QMP 27* IOThreads 28 29Commands 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 31commands. 32 33The daemon runs until it is stopped using the ``quit`` QMP command or 34SIGINT/SIGHUP/SIGTERM. 35 36**Warning:** Never modify images in use by a running virtual machine or any 37other process; this may destroy the image. Also, be aware that querying an 38image that is being modified by another process may encounter inconsistent 39state. 40 41Options 42------- 43 44.. program:: qemu-storage-daemon 45 46Standard options: 47 48.. option:: -h, --help 49 50 Display help and exit 51 52.. option:: -V, --version 53 54 Display version information and exit 55 56.. option:: -T, --trace [[enable=]PATTERN][,events=FILE][,file=FILE] 57 58 .. include:: ../qemu-option-trace.rst.inc 59 60.. option:: --blockdev BLOCKDEVDEF 61 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. 65 66.. option:: --chardev CHARDEVDEF 67 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:: 71 72 --chardev socket,id=char1,path=/tmp/qmp.sock,server,nowait 73 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>] 77 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). 81 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. 86 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). 93 94.. option:: --monitor MONITORDEF 95 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``:: 99 100 --monitor chardev=char1 101 102.. 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>] 104 105 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-* 107 secrets (see below). 108 109 To configure an NBD server on UNIX domain socket path ``/tmp/nbd.sock``:: 110 111 --nbd-server addr.type=unix,addr.path=/tmp/nbd.sock 112 113.. option:: --object help 114 --object <type>,help 115 --object <type>[,<property>=<value>...] 116 117 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. 120 121Examples 122-------- 123Launch the daemon with QMP monitor socket ``qmp.sock`` so clients can execute 124QMP commands:: 125 126 $ qemu-storage-daemon \ 127 --chardev socket,path=qmp.sock,server,nowait,id=char1 \ 128 --monitor chardev=char1 129 130Export raw image file ``disk.img`` over NBD UNIX domain socket ``nbd.sock``:: 131 132 $ 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 136 137Export a qcow2 image file ``disk.qcow2`` as a vhosts-user-blk device over UNIX 138domain socket ``vhost-user-blk.sock``:: 139 140 $ 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 144 145See also 146-------- 147 148:manpage:`qemu(1)`, :manpage:`qemu-block-drivers(7)`, :manpage:`qemu-storage-daemon-qmp-ref(7)` 149