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
is the disk image format. It is guessed automatically in most cases. The following formats are supported:
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 holes (for example in ext2 or ext3 on
Linux or NTFS on Windows), then only the written sectors will reserve
space. Use "qemu-img info" to know the real size used by the
image or "ls -ls" on Unix/Linux.
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.
Old QEMU image format. Left for compatibility.
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.
VMware 3 and 4 compatible image format.
Linux Compressed Loop image, useful only to reuse directly compressed
CD-ROM images present for example in the Knoppix CD-ROMs.
is the disk image size in kilobytes. Optional suffixes "M"
(megabyte) and "G" (gigabyte) are supported
is the destination disk image filename
is the destination format
indicates that target image must be compressed (qcow format only)
indicates that the target image must be encrypted (qcow format only)
indicates that the target image must use compatibility level 6 (vmdk format only)
indicates that the target image must be of type SCSI (vmdk format only)
Create the new disk image filename of size size and format
If base_image is specified, then the image will record only the
differences from base_image. No size needs to be specified in
this case. base_image will never be modified unless you use the
"commit" monitor command.
Commit the changes recorded in filename in its base image.
Convert the disk image filename to disk image output_filename
using format output_fmt. It can be optionnaly encrypted
("-e" option) or compressed ("-c" option).
Only the format "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 "qcow" or "cow": the empty sectors
are detected and suppressed from the destination image.
Give information about the disk image 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 HTML documentation of QEMU for more precise information and Linux
user mode emulator invocation.