below for further description.
@item -c
-indicates that target image must be compressed (qcow format only). If this
-option is used, copy offloading will not be attempted.
+indicates that target image must be compressed (qcow format only)
@item -h
with or without a command shows help and lists the supported formats
indicates the consecutive number of bytes that must contain only zeros
for qemu-img to create a sparse image during conversion. This value is rounded
down to the nearest 512 bytes. You may use the common size suffixes like
-@code{k} for kilobytes. If this option is used, copy offloading will not be
-attempted.
+@code{k} for kilobytes.
@item -t @var{cache}
specifies the cache mode that should be used with the (destination) file. See
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.
+@item -C
+Try to use copy offloading to move data from source image to target. This may
+improve performance if the data is remote, such as with NFS or iSCSI backends,
+but will not automatically sparsify zero sectors, and may result in a fully
+allocated target image depending on the host support for getting allocation
+information.
+@item --salvage
+Try to ignore I/O errors when reading. Unless in quiet mode (@code{-q}), errors
+will still be printed. Areas that cannot be read from the source will be
+treated as containing only zeroes.
@end table
Parameters to dd subcommand:
@table @option
-@item amend [--object @var{objectdef}] [--image-opts] [-p] [-p] [-f @var{fmt}] [-t @var{cache}] -o @var{options} @var{filename}
+@item amend [--object @var{objectdef}] [--image-opts] [-p] [-q] [-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.
Perform a consistency check on the disk image @var{filename}. The command can
output in the format @var{ofmt} which is either @code{human} or @code{json}.
+The JSON output is an object of QAPI type @code{ImageCheck}.
If @code{-r} is specified, qemu-img tries to repair any inconsistencies found
during the check. @code{-r leaks} repairs only cluster leaks, whereas
@end table
-@item convert [--object @var{objectdef}] [--image-opts] [--target-image-opts] [-U] [-c] [-p] [-q] [-n] [-f @var{fmt}] [-t @var{cache}] [-T @var{src_cache}] [-O @var{output_fmt}] [-B @var{backing_file}] [-o @var{options}] [-l @var{snapshot_param}] [-S @var{sparse_size}] [-m @var{num_coroutines}] [-W] @var{filename} [@var{filename2} [...]] @var{output_filename}
+@item convert [--object @var{objectdef}] [--image-opts] [--target-image-opts] [-U] [-C] [-c] [-p] [-q] [-n] [-f @var{fmt}] [-t @var{cache}] [-T @var{src_cache}] [-O @var{output_fmt}] [-B @var{backing_file}] [-o @var{options}] [-l @var{snapshot_param}] [-S @var{sparse_size}] [-m @var{num_coroutines}] [-W] @var{filename} [@var{filename2} [...]] @var{output_filename}
Convert the disk image @var{filename} or a snapshot @var{snapshot_param}
to disk image @var{output_filename} using format @var{output_fmt}. It can be optionally compressed (@code{-c}
Give information about the disk image @var{filename}. Use it in
particular to know the size reserved on disk which can be different
from the displayed size. If VM snapshots are stored in the disk image,
-they are displayed too. The command can output in the format @var{ofmt}
-which is either @code{human} or @code{json}.
+they are displayed too.
If a disk image has a backing file chain, information about each disk image in
the chain can be recursively enumerated by using the option @code{--backing-chain}.
qemu-img info --backing-chain snap2.qcow2
@end example
-@item map [-f @var{fmt}] [--output=@var{ofmt}] @var{filename}
+The command can output in the format @var{ofmt} which is either @code{human} or
+@code{json}. The JSON output is an object of QAPI type @code{ImageInfo}; with
+@code{--backing-chain}, it is an array of @code{ImageInfo} objects.
+
+@code{--output=human} reports the following information (for every image in the
+chain):
+@table @var
+@item image
+The image file name
+
+@item file format
+The image format
+
+@item virtual size
+The size of the guest disk
+
+@item disk size
+How much space the image file occupies on the host file system (may be shown as
+0 if this information is unavailable, e.g. because there is no file system)
+
+@item cluster_size
+Cluster size of the image format, if applicable
+
+@item encrypted
+Whether the image is encrypted (only present if so)
+
+@item cleanly shut down
+This is shown as @code{no} if the image is dirty and will have to be
+auto-repaired the next time it is opened in qemu.
+
+@item backing file
+The backing file name, if present
+
+@item backing file format
+The format of the backing file, if the image enforces it
+
+@item Snapshot list
+A list of all internal snapshots
+
+@item Format specific information
+Further information whose structure depends on the image format. This section
+is a textual representation of the respective @code{ImageInfoSpecific*} QAPI
+object (e.g. @code{ImageInfoSpecificQCow2} for qcow2 images).
+@end table
+
+@item map [--object @var{objectdef}] [--image-opts] [-f @var{fmt}] [--output=@var{ofmt}] [-U] @var{filename}
Dump the metadata of image @var{filename} and its backing file chain.
In particular, this commands dumps the allocation state of every sector
to size logical volumes or SAN LUNs appropriately for the image that will be
placed in them. The values reported are guaranteed to be large enough to fit
the image. The command can output in the format @var{ofmt} which is either
-@code{human} or @code{json}.
+@code{human} or @code{json}. The JSON output is an object of QAPI type
+@code{BlockMeasureInfo}.
If the size @var{N} is given then act as if creating a new empty image file
using @command{qemu-img create}. If @var{filename} is given then act as if
@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.
+@code{full} mode preallocates space for image by writing data to underlying
+storage. This data may or may not be zero, depending on the storage location.
@end table
@item qcow2
projects / qemu.git / blobdiff