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@example |
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@c man begin SYNOPSIS |
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usage: qemu-img command [command options] |
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@c man end |
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@end example |
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|
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@c man begin OPTIONS |
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|
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The following commands are supported: |
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|
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@include qemu-img-cmds.texi |
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|
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Command parameters: |
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@table @var |
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@item filename |
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is a disk image filename |
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@item fmt |
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is the disk image format. It is guessed automatically in most cases. See below |
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for a description of the supported disk formats. |
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|
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@item size |
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is the disk image size in bytes. Optional suffixes @code{k} or @code{K} |
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(kilobyte, 1024) @code{M} (megabyte, 1024k) and @code{G} (gigabyte, 1024M) |
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and T (terabyte, 1024G) are supported. @code{b} is ignored. |
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|
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@item output_filename |
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is the destination disk image filename |
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|
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@item output_fmt |
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is the destination format |
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@item options |
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is a comma separated list of format specific options in a |
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name=value format. Use @code{-o ?} for an overview of the options supported |
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by the used format or see the format descriptions below for details. |
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|
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|
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@item -c |
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indicates that target image must be compressed (qcow format only) |
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@item -h |
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with or without a command shows help and lists the supported formats |
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@end table |
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|
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Parameters to snapshot subcommand: |
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|
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@table @option |
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|
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@item snapshot |
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is the name of the snapshot to create, apply or delete |
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@item -a |
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applies a snapshot (revert disk to saved state) |
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@item -c |
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creates a snapshot |
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@item -d |
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deletes a snapshot |
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@item -l |
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lists all snapshots in the given image |
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@end table |
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|
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Command description: |
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|
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@table @option |
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@item create [-f @var{fmt}] [-o @var{options}] @var{filename} [@var{size}] |
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|
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Create the new disk image @var{filename} of size @var{size} and format |
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@var{fmt}. Depending on the file format, you can add one or more @var{options} |
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that enable additional features of this format. |
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|
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If the option @var{backing_file} is specified, then the image will record |
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only the differences from @var{backing_file}. No size needs to be specified in |
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this case. @var{backing_file} will never be modified unless you use the |
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@code{commit} monitor command (or qemu-img commit). |
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|
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The size can also be specified using the @var{size} option with @code{-o}, |
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it doesn't need to be specified separately in this case. |
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|
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@item commit [-f @var{fmt}] @var{filename} |
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|
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Commit the changes recorded in @var{filename} in its base image. |
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|
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@item convert [-c] [-f @var{fmt}] [-O @var{output_fmt}] [-o @var{options}] [-s @var{snapshot_name}] @var{filename} [@var{filename2} [...]] @var{output_filename} |
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|
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Convert the disk image @var{filename} or a snapshot @var{snapshot_name} to disk image @var{output_filename} |
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using format @var{output_fmt}. It can be optionally compressed (@code{-c} |
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option) or use any format specific options like encryption (@code{-o} option). |
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|
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Only the formats @code{qcow} and @code{qcow2} support compression. The |
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compression is read-only. It means that if a compressed sector is |
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rewritten, then it is rewritten as uncompressed data. |
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|
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Image conversion is also useful to get smaller image when using a |
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growable format such as @code{qcow} or @code{cow}: the empty sectors |
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are detected and suppressed from the destination image. |
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|
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You can use the @var{backing_file} option to force the output image to be |
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created as a copy on write image of the specified base image; the |
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@var{backing_file} should have the same content as the input's base image, |
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however the path, image format, etc may differ. |
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|
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@item info [-f @var{fmt}] @var{filename} |
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|
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Give information about the disk image @var{filename}. Use it in |
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particular to know the size reserved on disk which can be different |
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from the displayed size. If VM snapshots are stored in the disk image, |
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they are displayed too. |
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|
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@item snapshot [-l | -a @var{snapshot} | -c @var{snapshot} | -d @var{snapshot} ] @var{filename} |
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|
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List, apply, create or delete snapshots in image @var{filename}. |
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|
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@item resize @var{filename} [+ | -]@var{size} |
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|
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Change the disk image as if it had been created with @var{size}. |
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|
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Before using this command to shrink a disk image, you MUST use file system and |
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partitioning tools inside the VM to reduce allocated file systems and partition |
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sizes accordingly. Failure to do so will result in data loss! |
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|
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After using this command to grow a disk image, you must use file system and |
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partitioning tools inside the VM to actually begin using the new space on the |
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device. |
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@end table |
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|
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Supported image file formats: |
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|
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@table @option |
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@item raw |
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|
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Raw disk image format (default). This format has the advantage of |
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being simple and easily exportable to all other emulators. If your |
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file system supports @emph{holes} (for example in ext2 or ext3 on |
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Linux or NTFS on Windows), then only the written sectors will reserve |
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space. Use @code{qemu-img info} to know the real size used by the |
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image or @code{ls -ls} on Unix/Linux. |
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|
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@item host_device |
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|
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Host device format. This format should be used instead of raw when |
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converting to block devices or other devices where "holes" are not |
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supported. |
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|
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@item qcow2 |
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QEMU image format, the most versatile format. Use it to have smaller |
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images (useful if your filesystem does not supports holes, for example |
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on Windows), optional AES encryption, zlib based compression and |
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support of multiple VM snapshots. |
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|
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Supported options: |
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@table @code |
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@item backing_file |
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File name of a base image (see @option{create} subcommand) |
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@item backing_fmt |
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Image format of the base image |
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@item encryption |
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If this option is set to @code{on}, the image is encrypted. |
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|
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Encryption uses the AES format which is very secure (128 bit keys). Use |
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a long password (16 characters) to get maximum protection. |
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|
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@item cluster_size |
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Changes the qcow2 cluster size (must be between 512 and 2M). Smaller cluster |
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sizes can improve the image file size whereas larger cluster sizes generally |
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provide better performance. |
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|
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@item preallocation |
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Preallocation mode (allowed values: off, metadata). An image with preallocated |
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metadata is initially larger but can improve performance when the image needs |
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to grow. |
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|
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@end table |
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|
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|
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@item qcow |
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Old QEMU image format. Left for compatibility. |
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Supported options: |
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@table @code |
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@item backing_file |
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File name of a base image (see @option{create} subcommand) |
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@item encryption |
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If this option is set to @code{on}, the image is encrypted. |
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@end table |
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|
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@item cow |
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User Mode Linux Copy On Write image format. Used to be the only growable |
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image format in QEMU. It is supported only for compatibility with |
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previous versions. It does not work on win32. |
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@item vdi |
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VirtualBox 1.1 compatible image format. |
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@item vmdk |
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VMware 3 and 4 compatible image format. |
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|
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Supported options: |
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@table @code |
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@item backing_fmt |
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Image format of the base image |
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@item compat6 |
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Create a VMDK version 6 image (instead of version 4) |
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@end table |
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|
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@item vpc |
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VirtualPC compatible image format (VHD). |
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|
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@item cloop |
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Linux Compressed Loop image, useful only to reuse directly compressed |
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CD-ROM images present for example in the Knoppix CD-ROMs. |
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@end table |
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@c man end |
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@ignore |
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@setfilename qemu-img |
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@settitle QEMU disk image utility |
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|
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@c man begin SEEALSO |
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The HTML documentation of QEMU for more precise information and Linux |
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user mode emulator invocation. |
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@c man end |
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|
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@c man begin AUTHOR |
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Fabrice Bellard |
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@c man end |
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|
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@end ignore |