@example @c man begin SYNOPSIS @command{qemu-nbd} [OPTION]... @var{filename} @command{qemu-nbd} @option{-d} @var{dev} @c man end @end example @c man begin DESCRIPTION Export a QEMU disk image using the NBD protocol. @c man end @c man begin OPTIONS @var{filename} is a disk image filename, or a set of block driver options if @var{--image-opts} is specified. @var{dev} is an NBD device. @table @option @item --object type,id=@var{id},...props... Define a new instance of the @var{type} object class identified by @var{id}. See the @code{qemu(1)} manual page for full details of the properties supported. The common object types that it makes sense to define are the @code{secret} object, which is used to supply passwords and/or encryption keys, and the @code{tls-creds} object, which is used to supply TLS credentials for the qemu-nbd server. @item -p, --port=@var{port} The TCP port to listen on (default @samp{10809}) @item -o, --offset=@var{offset} The offset into the image @item -b, --bind=@var{iface} The interface to bind to (default @samp{0.0.0.0}) @item -k, --socket=@var{path} Use a unix socket with path @var{path} @item --image-opts Treat @var{filename} as a set of image options, instead of a plain filename. If this flag is specified, the @var{-f} flag should not be used, instead the '@code{format=}' option should be set. @item -f, --format=@var{fmt} Force the use of the block driver for format @var{fmt} instead of auto-detecting @item -r, --read-only Export the disk as read-only @item -P, --partition=@var{num} Only expose partition @var{num} @item -s, --snapshot Use @var{filename} as an external snapshot, create a temporary file with backing_file=@var{filename}, redirect the write to the temporary one @item -l, --load-snapshot=@var{snapshot_param} Load an internal snapshot inside @var{filename} and export it as an read-only device, @var{snapshot_param} format is 'snapshot.id=[ID],snapshot.name=[NAME]' or '[ID_OR_NAME]' @item -n, --nocache @itemx --cache=@var{cache} The cache mode to be used with the file. See the documentation of the emulator's @code{-drive cache=...} option for allowed values. @item --aio=@var{aio} Set the asynchronous I/O mode between @samp{threads} (the default) and @samp{native} (Linux only). @item --discard=@var{discard} Control whether @dfn{discard} (also known as @dfn{trim} or @dfn{unmap}) requests are ignored or passed to the filesystem. @var{discard} is one of @samp{ignore} (or @samp{off}), @samp{unmap} (or @samp{on}). The default is @samp{ignore}. @item --detect-zeroes=@var{detect-zeroes} Control the automatic conversion of plain zero writes by the OS to driver-specific optimized zero write commands. @var{detect-zeroes} is one of @samp{off}, @samp{on} or @samp{unmap}. @samp{unmap} converts a zero write to an unmap operation and can only be used if @var{discard} is set to @samp{unmap}. The default is @samp{off}. @item -c, --connect=@var{dev} Connect @var{filename} to NBD device @var{dev} @item -d, --disconnect Disconnect the device @var{dev} @item -e, --shared=@var{num} Allow up to @var{num} clients to share the device (default @samp{1}) @item -t, --persistent Don't exit on the last connection @item -x, --export-name=@var{name} Set the NBD volume export name. This switches the server to use the new style NBD protocol negotiation @item -D, --description=@var{description} Set the NBD volume export description, as a human-readable string. Requires the use of @option{-x} @item --tls-creds=ID Enable mandatory TLS encryption for the server by setting the ID of the TLS credentials object previously created with the --object option. @item --fork Fork off the server process and exit the parent once the server is running. @item -v, --verbose Display extra debugging information @item -h, --help Display this help and exit @item -V, --version Display version information and exit @item -T, --trace [[enable=]@var{pattern}][,events=@var{file}][,file=@var{file}] @findex --trace @include qemu-option-trace.texi @end table @c man end @ignore @setfilename qemu-nbd @settitle QEMU Disk Network Block Device Server @c man begin AUTHOR Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. @c man end @c man begin SEEALSO qemu(1), qemu-img(1) @c man end @end ignore