Archipelago » qemu

@example

@c man begin SYNOPSIS

usage: qemu-img command [command options]

@c man end

@end example

@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}] @var{filename} [-O @var{output_fmt}] @var{output_filename}

@item info [-f @var{fmt}] @var{filename}

@end table

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

@item size

is the disk image size in kilobytes. Optional suffixes @code{M}

(megabyte) and @code{G} (gigabyte) are supported

@item output_filename

is the destination disk image filename

@item output_fmt

 is the destination format

@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)

@end table

Command description:

@table @option

@item create [-6] [-e] [-b @var{base_image}] [-f @var{fmt}] @var{filename} [@var{size}]

Create the new disk image @var{filename} of size @var{size} and format

@var{fmt}.

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.

@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}

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).

Only the format @code{qcow} supports encryption or 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.

@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.

@end table

@c man end

@ignore

@setfilename qemu-img

@settitle QEMU disk image utility

@c man begin SEEALSO

The HTML documentation of QEMU for more precise information and Linux

user mode emulator invocation.

@c man end

@c man begin AUTHOR

Fabrice Bellard

@c man end

@end ignore