X-Git-Url: https://repo.jachan.dev/qemu.git/blobdiff_plain/ba9cef7b6e487a5a8969db81d09b8eec8a2b50c6..00b8ea4e34bf474ae55fc2fcb4ec12c0841d07e0:/qemu-img.texi diff --git a/qemu-img.texi b/qemu-img.texi index 55c6be391d..5b925ecf41 100644 --- a/qemu-img.texi +++ b/qemu-img.texi @@ -1,6 +1,6 @@ @example @c man begin SYNOPSIS -usage: qemu-img command [command options] +@command{qemu-img} [@var{standard} @var{options}] @var{command} [@var{command} @var{options}] @c man end @end example @@ -16,6 +16,17 @@ inconsistent state. @c man begin OPTIONS +Standard options: +@table @option +@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 + The following commands are supported: @include qemu-img-cmds.texi @@ -24,6 +35,28 @@ Command parameters: @table @var @item filename is a disk image filename + +@item --object @var{objectdef} + +is a QEMU user creatable object definition. See the @code{qemu(1)} manual +page for a description of the object properties. The most common object +type is a @code{secret}, which is used to supply passwords and/or encryption +keys. + +@item --image-opts + +Indicates that the source @var{filename} parameter is to be interpreted as a +full option string, not a plain filename. This parameter is mutually +exclusive with the @var{-f} parameter. + +@item --target-image-opts + +Indicates that the @var{output_filename} parameter(s) are to be interpreted as +a full option string, not a plain filename. This parameter is mutually +exclusive with the @var{-O} parameters. It is currently required to also use +the @var{-n} parameter to skip image creation. This restriction may be relaxed +in a future release. + @item fmt is the disk image format. It is guessed automatically in most cases. See below for a description of the supported disk formats. @@ -59,7 +92,8 @@ with or without a command shows help and lists the supported formats @item -p display progress bar (compare, convert and rebase commands only). If the @var{-p} option is not used for a command that supports it, the -progress is reported when the process receives a @code{SIGUSR1} signal. +progress is reported when the process receives a @code{SIGUSR1} or +@code{SIGINFO} signal. @item -q Quiet mode - do not print any output (except errors). There's no progress bar in case both @var{-q} and @var{-p} options are used. @@ -112,11 +146,57 @@ Parameters to convert subcommand: @item -n Skip the creation of the target volume +@item -m +Number of parallel coroutines for the convert process +@item -W +Allow out-of-order writes to the destination. This option improves performance, +but is only recommended for preallocated devices like host devices or other +raw block devices. +@end table + +Parameters to dd subcommand: + +@table @option + +@item bs=@var{block_size} +defines the block size +@item count=@var{blocks} +sets the number of input blocks to copy +@item if=@var{input} +sets the input file +@item of=@var{output} +sets the output file +@item skip=@var{blocks} +sets the number of input blocks to skip @end table Command description: @table @option +@item bench [-c @var{count}] [-d @var{depth}] [-f @var{fmt}] [--flush-interval=@var{flush_interval}] [-n] [--no-drain] [-o @var{offset}] [--pattern=@var{pattern}] [-q] [-s @var{buffer_size}] [-S @var{step_size}] [-t @var{cache}] [-w] @var{filename} + +Run a simple sequential I/O benchmark on the specified image. If @code{-w} is +specified, a write test is performed, otherwise a read test is performed. + +A total number of @var{count} I/O requests is performed, each @var{buffer_size} +bytes in size, and with @var{depth} requests in parallel. The first request +starts at the position given by @var{offset}, each following request increases +the current position by @var{step_size}. If @var{step_size} is not given, +@var{buffer_size} is used for its value. + +If @var{flush_interval} is specified for a write test, the request queue is +drained and a flush is issued before new writes are made whenever the number of +remaining requests is a multiple of @var{flush_interval}. If additionally +@code{--no-drain} is specified, a flush is issued without draining the request +queue first. + +If @code{-n} is specified, the native AIO backend is used if possible. On +Linux, this option only works if @code{-t none} or @code{-t directsync} is +specified as well. + +For write tests, by default a buffer filled with zeros is written. This can be +overridden with a pattern byte specified by @var{pattern}. + @item check [-f @var{fmt}] [--output=@var{ofmt}] [-r [leaks | all]] [-T @var{src_cache}] @var{filename} Perform a consistency check on the disk image @var{filename}. The command can @@ -153,7 +233,7 @@ If @code{-r} is specified, exit codes representing the image state refer to the state after (the attempt at) repairing it. That is, a successful @code{-r all} will yield the exit code 0, independently of the image state before. -@item create [-f @var{fmt}] [-o @var{options}] @var{filename} [@var{size}] +@item create [-f @var{fmt}] [-b @var{backing_file}] [-F @var{backing_fmt}] [-o @var{options}] @var{filename} [@var{size}] Create the new disk image @var{filename} of size @var{size} and format @var{fmt}. Depending on the file format, you can add one or more @var{options} @@ -231,7 +311,7 @@ Error on reading data @end table -@item convert [-c] [-p] [-n] [-f @var{fmt}] [-t @var{cache}] [-T @var{src_cache}] [-O @var{output_fmt}] [-o @var{options}] [-s @var{snapshot_id_or_name}] [-l @var{snapshot_param}] [-S @var{sparse_size}] @var{filename} [@var{filename2} [...]] @var{output_filename} +@item convert [-c] [-p] [-n] [-f @var{fmt}] [-t @var{cache}] [-T @var{src_cache}] [-O @var{output_fmt}] [-B @var{backing_file}] [-o @var{options}] [-s @var{snapshot_id_or_name}] [-l @var{snapshot_param}] [-m @var{num_coroutines}] [-W] [-S @var{sparse_size}] @var{filename} [@var{filename2} [...]] @var{output_filename} Convert the disk image @var{filename} or a snapshot @var{snapshot_param}(@var{snapshot_id_or_name} is deprecated) to disk image @var{output_filename} using format @var{output_fmt}. It can be optionally compressed (@code{-c} @@ -261,6 +341,25 @@ skipped. This is useful for formats such as @code{rbd} if the target volume has already been created with site specific options that cannot be supplied through qemu-img. +Out of order writes can be enabled with @code{-W} to improve performance. +This is only recommended for preallocated devices like host devices or other +raw block devices. Out of order write does not work in combination with +creating compressed images. + +@var{num_coroutines} specifies how many coroutines work in parallel during +the convert process (defaults to 8). + +@item dd [-f @var{fmt}] [-O @var{output_fmt}] [bs=@var{block_size}] [count=@var{blocks}] [skip=@var{blocks}] if=@var{input} of=@var{output} + +Dd copies from @var{input} file to @var{output} file converting it from +@var{fmt} format to @var{output_fmt} format. + +The data is by default read and written using blocks of 512 bytes but can be +modified by specifying @var{block_size}. If count=@var{blocks} is specified +dd will stop reading input after reading @var{blocks} input blocks. + +The size syntax is similar to dd(1)'s size syntax. + @item info [-f @var{fmt}] [--output=@var{ofmt}] [--backing-chain] @var{filename} Give information about the disk image @var{filename}. Use it in