@c man begin OPTIONS
The following commands are supported:
-@table @option
-@item create [-e] [-6] [-b @var{base_image}] [-f @var{fmt}] @var{filename} [@var{size}]
-@item commit [-f @var{fmt}] @var{filename}
-@item convert [-c] [-e] [-6] [-f @var{fmt}] [-O @var{output_fmt}] @var{filename} [@var{filename2} [...]] @var{output_filename}
-@item info [-f @var{fmt}] @var{filename}
-@end table
+
+@include qemu-img-cmds.texi
Command parameters:
@table @var
@item filename
is a disk image filename
-@item base_image
-is the read-only disk image which is used as base for a copy on
- write image; the copy on write image only stores the modified data
-
@item fmt
-is the disk image format. It is guessed automatically in most cases. The following formats are supported:
-
-@table @code
-@item raw
-
-Raw disk image format (default). This format has the advantage of
-being simple and easily exportable to all other emulators. If your
-file system supports @emph{holes} (for example in ext2 or ext3 on
-Linux or NTFS on Windows), then only the written sectors will reserve
-space. Use @code{qemu-img info} to know the real size used by the
-image or @code{ls -ls} on Unix/Linux.
-
-@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
-on Windows), optional AES encryption, zlib based compression and
-support of multiple VM snapshots.
-@item qcow
-Old QEMU image format. Left for compatibility.
-@item cow
-User Mode Linux Copy On Write image format. Used to be the only growable
-image format in QEMU. It is supported only for compatibility with
-previous versions. It does not work on win32.
-@item vmdk
-VMware 3 and 4 compatible image format.
-@item cloop
-Linux Compressed Loop image, useful only to reuse directly compressed
-CD-ROM images present for example in the Knoppix CD-ROMs.
-@end table
+is the disk image format. It is guessed automatically in most cases. See below
+for a description of the supported disk formats.
@item size
-is the disk image size in kilobytes. Optional suffixes @code{M}
-(megabyte) and @code{G} (gigabyte) are supported
+is the disk image size in bytes. Optional suffixes @code{k} or @code{K}
+(kilobyte, 1024) @code{M} (megabyte, 1024k) and @code{G} (gigabyte, 1024M)
+and T (terabyte, 1024G) are supported. @code{b} is ignored.
@item output_filename
is the destination disk image filename
@item output_fmt
is the destination format
+@item options
+is a comma separated list of format specific options in a
+name=value format. Use @code{-o ?} for an overview of the options supported
+by the used format or see the format descriptions below for details.
+
@item -c
indicates that target image must be compressed (qcow format only)
-@item -e
-indicates that the target image must be encrypted (qcow format only)
-@item -6
-indicates that the target image must use compatibility level 6 (vmdk format only)
+@item -h
+with or without a command shows help and lists the supported formats
+@item -p
+display progress bar (convert and rebase commands only)
+@end table
+
+Parameters to snapshot subcommand:
+
+@table @option
+
+@item snapshot
+is the name of the snapshot to create, apply or delete
+@item -a
+applies a snapshot (revert disk to saved state)
+@item -c
+creates a snapshot
+@item -d
+deletes a snapshot
+@item -l
+lists all snapshots in the given image
@end table
Command description:
@table @option
-@item create [-6] [-e] [-b @var{base_image}] [-f @var{fmt}] @var{filename} [@var{size}]
+@item check [-f @var{fmt}] @var{filename}
+
+Perform a consistency check on the disk image @var{filename}.
+
+Only the formats @code{qcow2}, @code{qed} and @code{vdi} support
+consistency checks.
+
+@item create [-f @var{fmt}] [-o @var{options}] @var{filename} [@var{size}]
Create the new disk image @var{filename} of size @var{size} and format
-@var{fmt}.
+@var{fmt}. Depending on the file format, you can add one or more @var{options}
+that enable additional features of this format.
-If @var{base_image} is specified, then the image will record only the
-differences from @var{base_image}. No size needs to be specified in
-this case. @var{base_image} will never be modified unless you use the
-@code{commit} monitor command.
+If the option @var{backing_file} is specified, then the image will record
+only the differences from @var{backing_file}. No size needs to be specified in
+this case. @var{backing_file} will never be modified unless you use the
+@code{commit} monitor command (or qemu-img commit).
+
+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}] @var{filename}
Commit the changes recorded in @var{filename} in its base image.
-@item convert [-c] [-e] [-f @var{fmt}] @var{filename} [-O @var{output_fmt}] @var{output_filename}
+@item convert [-c] [-p] [-f @var{fmt}] [-O @var{output_fmt}] [-o @var{options}] [-s @var{snapshot_name}] @var{filename} [@var{filename2} [...]] @var{output_filename}
-Convert the disk image @var{filename} to disk image @var{output_filename}
-using format @var{output_fmt}. It can be optionally encrypted
-(@code{-e} option) or compressed (@code{-c} option).
+Convert the disk image @var{filename} or a snapshot @var{snapshot_name} to disk image @var{output_filename}
+using format @var{output_fmt}. It can be optionally compressed (@code{-c}
+option) or use any format specific options like encryption (@code{-o} option).
-Only the format @code{qcow} supports encryption or compression. The
+Only the formats @code{qcow} and @code{qcow2} support compression. The
compression is read-only. It means that if a compressed sector is
rewritten, then it is rewritten as uncompressed data.
-Encryption uses the AES format which is very secure (128 bit keys). Use
-a long password (16 characters) to get maximum protection.
-
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.
+You can use the @var{backing_file} option to force the output image to be
+created as a copy on write image of the specified base image; the
+@var{backing_file} should have the same content as the input's base image,
+however the path, image format, etc may differ.
+
@item info [-f @var{fmt}] @var{filename}
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.
+
+@item snapshot [-l | -a @var{snapshot} | -c @var{snapshot} | -d @var{snapshot} ] @var{filename}
+
+List, apply, create or delete snapshots in image @var{filename}.
+
+@item rebase [-f @var{fmt}] [-p] [-u] -b @var{backing_file} [-F @var{backing_fmt}] @var{filename}
+
+Changes the backing file of an image. Only the formats @code{qcow2} and
+@code{qed} support changing the backing file.
+
+The backing file is changed to @var{backing_file} and (if the image format of
+@var{filename} supports this) the backing file format is changed to
+@var{backing_fmt}.
+
+There are two different modes in which @code{rebase} can operate:
+@table @option
+@item Safe mode
+This is the default mode and performs a real rebase operation. The new backing
+file may differ from the old one and qemu-img rebase will take care of keeping
+the guest-visible content of @var{filename} unchanged.
+
+In order to achieve this, any clusters that differ between @var{backing_file}
+and the old backing file of @var{filename} are merged into @var{filename}
+before actually changing the backing file.
+
+Note that the safe mode is an expensive operation, comparable to converting
+an image. It only works if the old backing file still exists.
+
+@item Unsafe mode
+qemu-img uses the unsafe mode if @code{-u} is specified. In this mode, only the
+backing file name and format of @var{filename} is changed without any checks
+on the file contents. The user must take care of specifying the correct new
+backing file, or the guest-visible content of the image will be corrupted.
+
+This mode is useful for renaming or moving the backing file to somewhere else.
+It can be used without an accessible old backing file, i.e. you can use it to
+fix an image whose backing file has already been moved/renamed.
+@end table
+
+@item resize @var{filename} [+ | -]@var{size}
+
+Change the disk image as if it had been created with @var{size}.
+
+Before using this command to shrink a disk image, you MUST use file system and
+partitioning tools inside the VM to reduce allocated file systems and partition
+sizes accordingly. Failure to do so will result in data loss!
+
+After using this command to grow a disk image, you must use file system and
+partitioning tools inside the VM to actually begin using the new space on the
+device.
@end table
+Supported image file formats:
+
+@table @option
+@item raw
+
+Raw disk image format (default). This format has the advantage of
+being simple and easily exportable to all other emulators. If your
+file system supports @emph{holes} (for example in ext2 or ext3 on
+Linux or NTFS on Windows), then only the written sectors will reserve
+space. Use @code{qemu-img info} to know the real size used by the
+image or @code{ls -ls} on Unix/Linux.
+
+@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
+on Windows), optional AES encryption, zlib based compression and
+support of multiple VM snapshots.
+
+Supported options:
+@table @code
+@item backing_file
+File name of a base image (see @option{create} subcommand)
+@item backing_fmt
+Image format of the base image
+@item encryption
+If this option is set to @code{on}, the image is encrypted.
+
+Encryption uses the AES format which is very secure (128 bit keys). Use
+a long password (16 characters) to get maximum protection.
+
+@item cluster_size
+Changes the qcow2 cluster size (must be between 512 and 2M). Smaller cluster
+sizes can improve the image file size whereas larger cluster sizes generally
+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.
+
+@end table
+
+
+@item qcow
+Old QEMU image format. Left for compatibility.
+
+Supported options:
+@table @code
+@item backing_file
+File name of a base image (see @option{create} subcommand)
+@item encryption
+If this option is set to @code{on}, the image is encrypted.
+@end table
+
+@item cow
+User Mode Linux Copy On Write image format. Used to be the only growable
+image format in QEMU. It is supported only for compatibility with
+previous versions. It does not work on win32.
+@item vdi
+VirtualBox 1.1 compatible image format.
+@item vmdk
+VMware 3 and 4 compatible image format.
+
+Supported options:
+@table @code
+@item backing_fmt
+Image format of the base image
+@item compat6
+Create a VMDK version 6 image (instead of version 4)
+@end table
+
+@item vpc
+VirtualPC compatible image format (VHD).
+
+@item cloop
+Linux Compressed Loop image, useful only to reuse directly compressed
+CD-ROM images present for example in the Knoppix CD-ROMs.
+@end table
+
+
@c man end
@ignore
projects / qemu.git / blobdiff