@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
@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
@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 @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} and @var{-F} parameters.
+
@item fmt
is the disk image format. It is guessed automatically in most cases. See below
for a description of the supported disk formats.
the documentation of the emulator's @code{-drive cache=...} option for allowed
values.
@item -T @var{src_cache}
-in contrast specifies the cache mode that should be used with the source
-file(s).
+specifies the cache mode that should be used with the source file(s). See
+the documentation of the emulator's @code{-drive cache=...} option for allowed
+values.
@end table
Parameters to snapshot subcommand:
@item -F
Second image format
@item -s
-Strict mode - fail on on different image size or sector allocation
+Strict mode - fail on different image size or sector allocation
@end table
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
The size can also be specified using the @var{size} option with @code{-o},
it doesn't need to be specified separately in this case.
-@item commit [-f @var{fmt}] [-t @var{cache}] @var{filename}
+@item commit [-q] [-f @var{fmt}] [-t @var{cache}] [-b @var{base}] [-d] [-p] @var{filename}
Commit the changes recorded in @var{filename} in its base image or backing file.
If the backing file is smaller than the snapshot, then the backing file will be
backing file to match the size of the smaller snapshot, you can safely truncate
it yourself once the commit operation successfully completes.
+The image @var{filename} is emptied after the operation has succeeded. If you do
+not need @var{filename} afterwards and intend to drop it, you may skip emptying
+@var{filename} by specifying the @code{-d} flag.
+
+If the backing chain of the given image file @var{filename} has more than one
+layer, the backing file into which the changes will be committed may be
+specified as @var{base} (which has to be part of @var{filename}'s backing
+chain). If @var{base} is not specified, the immediate backing file of the top
+image (which is @var{filename}) will be used. For reasons of consistency,
+explicitly specifying @var{base} will always imply @code{-d} (since emptying an
+image after committing to an indirect backing file would lead to different data
+being read from the image due to content in the intermediate backing chain
+overruling the commit target).
+
@item compare [-f @var{fmt}] [-F @var{fmt}] [-T @var{src_cache}] [-p] [-s] [-q] @var{filename1} @var{filename2}
Check if two images have the same content. You can compare images with
@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}
rewritten, then it is rewritten as uncompressed data.
Image conversion is also useful to get smaller image when using a
-growable format such as @code{qcow} or @code{cow}: the empty sectors
-are detected and suppressed from the destination image.
+growable format such as @code{qcow}: the empty sectors are detected and
+suppressed from the destination image.
@var{sparse_size} indicates the consecutive number of bytes (defaults to 4k)
that must contain only zeros for qemu-img to create a sparse image during
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
independently of any backing file).
@var{cache} specifies the cache mode to be used for @var{filename}, whereas
-@var{src_cache} specifies the cache mode for reading the new backing file.
+@var{src_cache} specifies the cache mode for reading backing files.
There are two different modes in which @code{rebase} can operate:
@table @option
partitioning tools inside the VM to actually begin using the new space on the
device.
-@item amend [-f @var{fmt}] -o @var{options} @var{filename}
+@item amend [-p] [-f @var{fmt}] [-t @var{cache}] -o @var{options} @var{filename}
Amends the image format specific @var{options} for the image file
@var{filename}. Not all file formats support this operation.
space. Use @code{qemu-img info} to know the real size used by the
image or @code{ls -ls} on Unix/Linux.
+Supported options:
+@table @code
+@item preallocation
+Preallocation mode (allowed values: @code{off}, @code{falloc}, @code{full}).
+@code{falloc} mode preallocates space for image by calling posix_fallocate().
+@code{full} mode preallocates space for image by writing zeros to underlying
+storage.
+@end table
+
@item qcow2
QEMU image format, the most versatile format. Use it to have smaller
images (useful if your filesystem does not supports holes, for example
provide better performance.
@item preallocation
-Preallocation mode (allowed values: off, metadata). An image with preallocated
-metadata is initially larger but can improve performance when the image needs
-to grow.
+Preallocation mode (allowed values: @code{off}, @code{metadata}, @code{falloc},
+@code{full}). An image with preallocated metadata is initially larger but can
+improve performance when the image needs to grow. @code{falloc} and @code{full}
+preallocations are like the same options of @code{raw} format, but sets up
+metadata also.
@item lazy_refcounts
If this option is set to @code{on}, reference count updates are postponed with
projects / mirror_qemu.git / blobdiff