File:  [Qemu by Fabrice Bellard] / qemu / qemu-img.texi
Revision (vendor branch): download - view: text, annotated - select for diffs
Tue Apr 24 16:51:01 2018 UTC (3 years, 1 month ago) by root
Branches: qemu, MAIN
CVS tags: qemu0105, qemu0104, qemu0103, qemu0102, qemu0101, qemu0100, HEAD
qemu 0.10.0

    1: @example
    2: @c man begin SYNOPSIS
    3: usage: qemu-img command [command options]
    4: @c man end
    5: @end example
    7: @c man begin OPTIONS
    9: The following commands are supported:
   10: @table @option
   11: @item create [-e] [-6] [-b @var{base_image}] [-f @var{fmt}] @var{filename} [@var{size}]
   12: @item commit [-f @var{fmt}] @var{filename}
   13: @item convert [-c] [-e] [-6] [-f @var{fmt}] [-O @var{output_fmt}] [-B @var{output_base_image}] @var{filename} [@var{filename2} [...]] @var{output_filename}
   14: @item info [-f @var{fmt}] @var{filename}
   15: @item snapshot [-l | -a @var{snapshot} | -c @var{snapshot} | -d @var{snapshot}] @var{filename}
   16: @end table
   18: Command parameters:
   19: @table @var
   20: @item filename
   21:  is a disk image filename
   22: @item base_image
   23: is the read-only disk image which is used as base for a copy on
   24:     write image; the copy on write image only stores the modified data
   25: @item output_base_image
   26: forces the output image to be created as a copy on write
   27: image of the specified base image; @code{output_base_image} should have the same
   28: content as the input's base image, however the path, image format, etc may
   29: differ
   30: @item fmt
   31: is the disk image format. It is guessed automatically in most cases. The following formats are supported:
   33: @table @code
   34: @item raw
   36: Raw disk image format (default). This format has the advantage of
   37: being simple and easily exportable to all other emulators. If your
   38: file system supports @emph{holes} (for example in ext2 or ext3 on
   39: Linux or NTFS on Windows), then only the written sectors will reserve
   40: space. Use @code{qemu-img info} to know the real size used by the
   41: image or @code{ls -ls} on Unix/Linux.
   43: @item qcow2
   44: QEMU image format, the most versatile format. Use it to have smaller
   45: images (useful if your filesystem does not supports holes, for example
   46: on Windows), optional AES encryption, zlib based compression and
   47: support of multiple VM snapshots.
   48: @item qcow
   49: Old QEMU image format. Left for compatibility.
   50: @item cow
   51: User Mode Linux Copy On Write image format. Used to be the only growable
   52: image format in QEMU. It is supported only for compatibility with
   53: previous versions. It does not work on win32.
   54: @item vmdk
   55: VMware 3 and 4 compatible image format.
   56: @item cloop
   57: Linux Compressed Loop image, useful only to reuse directly compressed
   58: CD-ROM images present for example in the Knoppix CD-ROMs.
   59: @end table
   61: @item size
   62: is the disk image size in kilobytes. Optional suffixes @code{M}
   63: (megabyte, 1024 * 1024) and @code{G} (gigabyte, 1024 * 1024 * 1024)
   64: are supported and any @code{k} or @code{K} is ignored.
   66: @item output_filename
   67: is the destination disk image filename
   69: @item output_fmt
   70:  is the destination format
   72: @item -c
   73: indicates that target image must be compressed (qcow format only)
   74: @item -e
   75: indicates that the target image must be encrypted (qcow format only)
   76: @item -6
   77: indicates that the target image must use compatibility level 6 (vmdk format only)
   78: @item -h
   79: with or without a command shows help and lists the supported formats
   80: @end table
   82: Parameters to snapshot subcommand:
   84: @table @option
   86: @item snapshot
   87: is the name of the snapshot to create, apply or delete
   88: @item -a
   89: applies a snapshot (revert disk to saved state)
   90: @item -c
   91: creates a snapshot
   92: @item -d
   93: deletes a snapshot
   94: @item -l
   95: lists all snapshots in the given image
   96: @end table
   98: Command description:
  100: @table @option
  101: @item create [-6] [-e] [-b @var{base_image}] [-f @var{fmt}] @var{filename} [@var{size}]
  103: Create the new disk image @var{filename} of size @var{size} and format
  104: @var{fmt}.
  106: If @var{base_image} is specified, then the image will record only the
  107: differences from @var{base_image}. No size needs to be specified in
  108: this case. @var{base_image} will never be modified unless you use the
  109: @code{commit} monitor command.
  111: @item commit [-f @var{fmt}] @var{filename}
  113: Commit the changes recorded in @var{filename} in its base image.
  115: @item convert [-c] [-e] [-f @var{fmt}] @var{filename} [-O @var{output_fmt}] @var{output_filename}
  117: Convert the disk image @var{filename} to disk image @var{output_filename}
  118: using format @var{output_fmt}. It can be optionally encrypted
  119: (@code{-e} option) or compressed (@code{-c} option).
  121: Only the format @code{qcow} supports encryption or compression. The
  122: compression is read-only. It means that if a compressed sector is
  123: rewritten, then it is rewritten as uncompressed data.
  125: Encryption uses the AES format which is very secure (128 bit keys). Use
  126: a long password (16 characters) to get maximum protection.
  128: Image conversion is also useful to get smaller image when using a
  129: growable format such as @code{qcow} or @code{cow}: the empty sectors
  130: are detected and suppressed from the destination image.
  132: @item info [-f @var{fmt}] @var{filename}
  134: Give information about the disk image @var{filename}. Use it in
  135: particular to know the size reserved on disk which can be different
  136: from the displayed size. If VM snapshots are stored in the disk image,
  137: they are displayed too.
  139: @item snapshot [-l | -a @var{snapshot} | -c @var{snapshot} | -d @var{snapshot} ] @var{filename}
  141: List, apply, create or delete snapshots in image @var{filename}.
  142: @end table
  144: @c man end
  146: @ignore
  148: @setfilename qemu-img
  149: @settitle QEMU disk image utility
  151: @c man begin SEEALSO
  152: The HTML documentation of QEMU for more precise information and Linux
  153: user mode emulator invocation.
  154: @c man end
  156: @c man begin AUTHOR
  157: Fabrice Bellard
  158: @c man end
  160: @end ignore