02854532c2
People shouldn't explicitly specify host_device any more. raw is doing the Right Thing. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
261 lines
8.5 KiB
Plaintext
261 lines
8.5 KiB
Plaintext
@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:
|
|
|
|
@include qemu-img-cmds.texi
|
|
|
|
Command parameters:
|
|
@table @var
|
|
@item filename
|
|
is a disk image filename
|
|
@item fmt
|
|
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 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 -h
|
|
with or without a command shows help and lists the supported formats
|
|
@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 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}. Depending on the file format, you can add one or more @var{options}
|
|
that enable additional features of this format.
|
|
|
|
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] [-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} 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 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.
|
|
|
|
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}] [-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
|
|
|
|
@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
|