X-Git-Url: https://git.proxmox.com/?a=blobdiff_plain;f=qemu-img.texi;h=c81db3e81cd0f9a4ec356790682f3bda7694b37e;hb=a6c76285f2e41535527a46edf4d158a2779545e1;hp=afaebdd408e9cfaf363d2ecf53aeba322d4309fe;hpb=8eb779e4223a18db9838a49ece1bc72cfdfb7761;p=mirror_qemu.git diff --git a/qemu-img.texi b/qemu-img.texi index afaebdd408..c81db3e81c 100644 --- a/qemu-img.texi +++ b/qemu-img.texi @@ -1,6 +1,6 @@ @example @c man begin SYNOPSIS -@command{qemu-img} @var{command} [@var{command} @var{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 @@ -126,11 +137,57 @@ 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 @@ -245,7 +302,7 @@ 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}] [-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} @@ -275,6 +332,25 @@ 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