3 @command{qemu-img} [@var{standard} @var{options}] @var{command} [@var{command} @var{options}]
7 @c man begin DESCRIPTION
8 qemu-img allows you to create, convert and modify images offline. It can handle
9 all image formats supported by QEMU.
11 @b{Warning:} Never use qemu-img to modify images in use by a running virtual
12 machine or any other process; this may destroy the image. Also, be aware that
13 querying an image that is being modified by another process may encounter
22 Display this help and exit
24 Display version information and exit
25 @item -T, --trace [[enable=]@var{pattern}][,events=@var{file}][,file=@var{file}]
27 @include qemu-option-trace.texi
30 The following commands are supported:
32 @include qemu-img-cmds.texi
37 is a disk image filename
39 @item --object @var{objectdef}
41 is a QEMU user creatable object definition. See the @code{qemu(1)} manual
42 page for a description of the object properties. The most common object
43 type is a @code{secret}, which is used to supply passwords and/or encryption
48 Indicates that the source @var{filename} parameter is to be interpreted as a
49 full option string, not a plain filename. This parameter is mutually
50 exclusive with the @var{-f} parameter.
52 @item --target-image-opts
54 Indicates that the @var{output_filename} parameter(s) are to be interpreted as
55 a full option string, not a plain filename. This parameter is mutually
56 exclusive with the @var{-O} parameters. It is currently required to also use
57 the @var{-n} parameter to skip image creation. This restriction may be relaxed
61 is the disk image format. It is guessed automatically in most cases. See below
62 for a description of the supported disk formats.
65 will enumerate information about backing files in a disk image chain. Refer
66 below for further description.
69 is the disk image size in bytes. Optional suffixes @code{k} or @code{K}
70 (kilobyte, 1024) @code{M} (megabyte, 1024k) and @code{G} (gigabyte, 1024M)
71 and T (terabyte, 1024G) are supported. @code{b} is ignored.
74 is the destination disk image filename
77 is the destination format
79 is a comma separated list of format specific options in a
80 name=value format. Use @code{-o ?} for an overview of the options supported
81 by the used format or see the format descriptions below for details.
83 is param used for internal snapshot, format is
84 'snapshot.id=[ID],snapshot.name=[NAME]' or '[ID_OR_NAME]'
85 @item snapshot_id_or_name
86 is deprecated, use snapshot_param instead
89 indicates that target image must be compressed (qcow format only)
91 with or without a command shows help and lists the supported formats
93 display progress bar (compare, convert and rebase commands only).
94 If the @var{-p} option is not used for a command that supports it, the
95 progress is reported when the process receives a @code{SIGUSR1} or
96 @code{SIGINFO} signal.
98 Quiet mode - do not print any output (except errors). There's no progress bar
99 in case both @var{-q} and @var{-p} options are used.
101 indicates the consecutive number of bytes that must contain only zeros
102 for qemu-img to create a sparse image during conversion. This value is rounded
103 down to the nearest 512 bytes. You may use the common size suffixes like
104 @code{k} for kilobytes.
106 specifies the cache mode that should be used with the (destination) file. See
107 the documentation of the emulator's @code{-drive cache=...} option for allowed
109 @item -T @var{src_cache}
110 specifies the cache mode that should be used with the source file(s). See
111 the documentation of the emulator's @code{-drive cache=...} option for allowed
115 Parameters to snapshot subcommand:
120 is the name of the snapshot to create, apply or delete
122 applies a snapshot (revert disk to saved state)
128 lists all snapshots in the given image
131 Parameters to compare subcommand:
140 Strict mode - fail on different image size or sector allocation
143 Parameters to convert subcommand:
148 Skip the creation of the target volume
150 Number of parallel coroutines for the convert process
152 Allow out-of-order writes to the destination. This option improves performance,
153 but is only recommended for preallocated devices like host devices or other
157 Parameters to dd subcommand:
161 @item bs=@var{block_size}
162 defines the block size
163 @item count=@var{blocks}
164 sets the number of input blocks to copy
167 @item of=@var{output}
169 @item skip=@var{blocks}
170 sets the number of input blocks to skip
176 @item bench [-c @var{count}] [-d @var{depth}] [-f @var{fmt}] [--flush-interval=@var{flush_interval}] [-n] [--no-drain] [-o @var{offset}] [--pattern=@var{pattern}] [-q] [-s @var{buffer_size}] [-S @var{step_size}] [-t @var{cache}] [-w] @var{filename}
178 Run a simple sequential I/O benchmark on the specified image. If @code{-w} is
179 specified, a write test is performed, otherwise a read test is performed.
181 A total number of @var{count} I/O requests is performed, each @var{buffer_size}
182 bytes in size, and with @var{depth} requests in parallel. The first request
183 starts at the position given by @var{offset}, each following request increases
184 the current position by @var{step_size}. If @var{step_size} is not given,
185 @var{buffer_size} is used for its value.
187 If @var{flush_interval} is specified for a write test, the request queue is
188 drained and a flush is issued before new writes are made whenever the number of
189 remaining requests is a multiple of @var{flush_interval}. If additionally
190 @code{--no-drain} is specified, a flush is issued without draining the request
193 If @code{-n} is specified, the native AIO backend is used if possible. On
194 Linux, this option only works if @code{-t none} or @code{-t directsync} is
197 For write tests, by default a buffer filled with zeros is written. This can be
198 overridden with a pattern byte specified by @var{pattern}.
200 @item check [-f @var{fmt}] [--output=@var{ofmt}] [-r [leaks | all]] [-T @var{src_cache}] @var{filename}
202 Perform a consistency check on the disk image @var{filename}. The command can
203 output in the format @var{ofmt} which is either @code{human} or @code{json}.
205 If @code{-r} is specified, qemu-img tries to repair any inconsistencies found
206 during the check. @code{-r leaks} repairs only cluster leaks, whereas
207 @code{-r all} fixes all kinds of errors, with a higher risk of choosing the
208 wrong fix or hiding corruption that has already occurred.
210 Only the formats @code{qcow2}, @code{qed} and @code{vdi} support
213 In case the image does not have any inconsistencies, check exits with @code{0}.
214 Other exit codes indicate the kind of inconsistency found or if another error
215 occurred. The following table summarizes all exit codes of the check subcommand:
220 Check completed, the image is (now) consistent
222 Check not completed because of internal errors
224 Check completed, image is corrupted
226 Check completed, image has leaked clusters, but is not corrupted
228 Checks are not supported by the image format
232 If @code{-r} is specified, exit codes representing the image state refer to the
233 state after (the attempt at) repairing it. That is, a successful @code{-r all}
234 will yield the exit code 0, independently of the image state before.
236 @item create [-f @var{fmt}] [-b @var{backing_file}] [-F @var{backing_fmt}] [-u] [-o @var{options}] @var{filename} [@var{size}]
238 Create the new disk image @var{filename} of size @var{size} and format
239 @var{fmt}. Depending on the file format, you can add one or more @var{options}
240 that enable additional features of this format.
242 If the option @var{backing_file} is specified, then the image will record
243 only the differences from @var{backing_file}. No size needs to be specified in
244 this case. @var{backing_file} will never be modified unless you use the
245 @code{commit} monitor command (or qemu-img commit).
247 If a relative path name is given, the backing file is looked up relative to
248 the directory containing @var{filename}.
250 Note that a given backing file will be opened to check that it is valid. Use
251 the @code{-u} option to enable unsafe backing file mode, which means that the
252 image will be created even if the associated backing file cannot be opened. A
253 matching backing file must be created or additional options be used to make the
254 backing file specification valid when you want to use an image created this
257 The size can also be specified using the @var{size} option with @code{-o},
258 it doesn't need to be specified separately in this case.
260 @item commit [-q] [-f @var{fmt}] [-t @var{cache}] [-b @var{base}] [-d] [-p] @var{filename}
262 Commit the changes recorded in @var{filename} in its base image or backing file.
263 If the backing file is smaller than the snapshot, then the backing file will be
264 resized to be the same size as the snapshot. If the snapshot is smaller than
265 the backing file, the backing file will not be truncated. If you want the
266 backing file to match the size of the smaller snapshot, you can safely truncate
267 it yourself once the commit operation successfully completes.
269 The image @var{filename} is emptied after the operation has succeeded. If you do
270 not need @var{filename} afterwards and intend to drop it, you may skip emptying
271 @var{filename} by specifying the @code{-d} flag.
273 If the backing chain of the given image file @var{filename} has more than one
274 layer, the backing file into which the changes will be committed may be
275 specified as @var{base} (which has to be part of @var{filename}'s backing
276 chain). If @var{base} is not specified, the immediate backing file of the top
277 image (which is @var{filename}) will be used. Note that after a commit operation
278 all images between @var{base} and the top image will be invalid and may return
279 garbage data when read. For this reason, @code{-b} implies @code{-d} (so that
280 the top image stays valid).
282 @item compare [-f @var{fmt}] [-F @var{fmt}] [-T @var{src_cache}] [-p] [-s] [-q] @var{filename1} @var{filename2}
284 Check if two images have the same content. You can compare images with
285 different format or settings.
287 The format is probed unless you specify it by @var{-f} (used for
288 @var{filename1}) and/or @var{-F} (used for @var{filename2}) option.
290 By default, images with different size are considered identical if the larger
291 image contains only unallocated and/or zeroed sectors in the area after the end
292 of the other image. In addition, if any sector is not allocated in one image
293 and contains only zero bytes in the second one, it is evaluated as equal. You
294 can use Strict mode by specifying the @var{-s} option. When compare runs in
295 Strict mode, it fails in case image size differs or a sector is allocated in
296 one image and is not allocated in the second one.
298 By default, compare prints out a result message. This message displays
299 information that both images are same or the position of the first different
300 byte. In addition, result message can report different image size in case
303 Compare exits with @code{0} in case the images are equal and with @code{1}
304 in case the images differ. Other exit codes mean an error occurred during
305 execution and standard error output should contain an error message.
306 The following table sumarizes all exit codes of the compare subcommand:
315 Error on opening an image
317 Error on checking a sector allocation
319 Error on reading data
323 @item convert [-c] [-p] [-n] [-f @var{fmt}] [-t @var{cache}] [-T @var{src_cache}] [-O @var{output_fmt}] [-B @var{backing_file}] [-o @var{options}] [-s @var{snapshot_id_or_name}] [-l @var{snapshot_param}] [-m @var{num_coroutines}] [-W] [-S @var{sparse_size}] @var{filename} [@var{filename2} [...]] @var{output_filename}
325 Convert the disk image @var{filename} or a snapshot @var{snapshot_param}(@var{snapshot_id_or_name} is deprecated)
326 to disk image @var{output_filename} using format @var{output_fmt}. It can be optionally compressed (@code{-c}
327 option) or use any format specific options like encryption (@code{-o} option).
329 Only the formats @code{qcow} and @code{qcow2} support compression. The
330 compression is read-only. It means that if a compressed sector is
331 rewritten, then it is rewritten as uncompressed data.
333 Image conversion is also useful to get smaller image when using a
334 growable format such as @code{qcow}: the empty sectors are detected and
335 suppressed from the destination image.
337 @var{sparse_size} indicates the consecutive number of bytes (defaults to 4k)
338 that must contain only zeros for qemu-img to create a sparse image during
339 conversion. If @var{sparse_size} is 0, the source will not be scanned for
340 unallocated or zero sectors, and the destination image will always be
343 You can use the @var{backing_file} option to force the output image to be
344 created as a copy on write image of the specified base image; the
345 @var{backing_file} should have the same content as the input's base image,
346 however the path, image format, etc may differ.
348 If a relative path name is given, the backing file is looked up relative to
349 the directory containing @var{output_filename}.
351 If the @code{-n} option is specified, the target volume creation will be
352 skipped. This is useful for formats such as @code{rbd} if the target
353 volume has already been created with site specific options that cannot
354 be supplied through qemu-img.
356 Out of order writes can be enabled with @code{-W} to improve performance.
357 This is only recommended for preallocated devices like host devices or other
358 raw block devices. Out of order write does not work in combination with
359 creating compressed images.
361 @var{num_coroutines} specifies how many coroutines work in parallel during
362 the convert process (defaults to 8).
364 @item dd [-f @var{fmt}] [-O @var{output_fmt}] [bs=@var{block_size}] [count=@var{blocks}] [skip=@var{blocks}] if=@var{input} of=@var{output}
366 Dd copies from @var{input} file to @var{output} file converting it from
367 @var{fmt} format to @var{output_fmt} format.
369 The data is by default read and written using blocks of 512 bytes but can be
370 modified by specifying @var{block_size}. If count=@var{blocks} is specified
371 dd will stop reading input after reading @var{blocks} input blocks.
373 The size syntax is similar to dd(1)'s size syntax.
375 @item info [-f @var{fmt}] [--output=@var{ofmt}] [--backing-chain] @var{filename}
377 Give information about the disk image @var{filename}. Use it in
378 particular to know the size reserved on disk which can be different
379 from the displayed size. If VM snapshots are stored in the disk image,
380 they are displayed too. The command can output in the format @var{ofmt}
381 which is either @code{human} or @code{json}.
383 If a disk image has a backing file chain, information about each disk image in
384 the chain can be recursively enumerated by using the option @code{--backing-chain}.
386 For instance, if you have an image chain like:
389 base.qcow2 <- snap1.qcow2 <- snap2.qcow2
392 To enumerate information about each disk image in the above chain, starting from top to base, do:
395 qemu-img info --backing-chain snap2.qcow2
398 @item map [-f @var{fmt}] [--output=@var{ofmt}] @var{filename}
400 Dump the metadata of image @var{filename} and its backing file chain.
401 In particular, this commands dumps the allocation state of every sector
402 of @var{filename}, together with the topmost file that allocates it in
403 the backing file chain.
405 Two option formats are possible. The default format (@code{human})
406 only dumps known-nonzero areas of the file. Known-zero parts of the
407 file are omitted altogether, and likewise for parts that are not allocated
408 throughout the chain. @command{qemu-img} output will identify a file
409 from where the data can be read, and the offset in the file. Each line
410 will include four fields, the first three of which are hexadecimal
411 numbers. For example the first line of:
413 Offset Length Mapped to File
414 0 0x20000 0x50000 /tmp/overlay.qcow2
415 0x100000 0x10000 0x95380000 /tmp/backing.qcow2
418 means that 0x20000 (131072) bytes starting at offset 0 in the image are
419 available in /tmp/overlay.qcow2 (opened in @code{raw} format) starting
420 at offset 0x50000 (327680). Data that is compressed, encrypted, or
421 otherwise not available in raw format will cause an error if @code{human}
422 format is in use. Note that file names can include newlines, thus it is
423 not safe to parse this output format in scripts.
425 The alternative format @code{json} will return an array of dictionaries
426 in JSON format. It will include similar information in
427 the @code{start}, @code{length}, @code{offset} fields;
428 it will also include other more specific information:
431 whether the sectors contain actual data or not (boolean field @code{data};
432 if false, the sectors are either unallocated or stored as optimized
436 whether the data is known to read as zero (boolean field @code{zero});
439 in order to make the output shorter, the target file is expressed as
440 a @code{depth}; for example, a depth of 2 refers to the backing file
441 of the backing file of @var{filename}.
444 In JSON format, the @code{offset} field is optional; it is absent in
445 cases where @code{human} format would omit the entry or exit with an error.
446 If @code{data} is false and the @code{offset} field is present, the
447 corresponding sectors in the file are not yet in use, but they are
450 For more information, consult @file{include/block/block.h} in QEMU's
453 @item measure [--output=@var{ofmt}] [-O @var{output_fmt}] [-o @var{options}] [--size @var{N} | [--object @var{objectdef}] [--image-opts] [-f @var{fmt}] [-l @var{snapshot_param}] @var{filename}]
455 Calculate the file size required for a new image. This information can be used
456 to size logical volumes or SAN LUNs appropriately for the image that will be
457 placed in them. The values reported are guaranteed to be large enough to fit
458 the image. The command can output in the format @var{ofmt} which is either
459 @code{human} or @code{json}.
461 If the size @var{N} is given then act as if creating a new empty image file
462 using @command{qemu-img create}. If @var{filename} is given then act as if
463 converting an existing image file using @command{qemu-img convert}. The format
464 of the new file is given by @var{output_fmt} while the format of an existing
465 file is given by @var{fmt}.
467 A snapshot in an existing image can be specified using @var{snapshot_param}.
469 The following fields are reported:
471 required size: 524288
472 fully allocated size: 1074069504
475 The @code{required size} is the file size of the new image. It may be smaller
476 than the virtual disk size if the image format supports compact representation.
478 The @code{fully allocated size} is the file size of the new image once data has
479 been written to all sectors. This is the maximum size that the image file can
480 occupy with the exception of internal snapshots, dirty bitmaps, vmstate data,
481 and other advanced image format features.
483 @item snapshot [-l | -a @var{snapshot} | -c @var{snapshot} | -d @var{snapshot} ] @var{filename}
485 List, apply, create or delete snapshots in image @var{filename}.
487 @item rebase [-f @var{fmt}] [-t @var{cache}] [-T @var{src_cache}] [-p] [-u] -b @var{backing_file} [-F @var{backing_fmt}] @var{filename}
489 Changes the backing file of an image. Only the formats @code{qcow2} and
490 @code{qed} support changing the backing file.
492 The backing file is changed to @var{backing_file} and (if the image format of
493 @var{filename} supports this) the backing file format is changed to
494 @var{backing_fmt}. If @var{backing_file} is specified as ``'' (the empty
495 string), then the image is rebased onto no backing file (i.e. it will exist
496 independently of any backing file).
498 If a relative path name is given, the backing file is looked up relative to
499 the directory containing @var{filename}.
501 @var{cache} specifies the cache mode to be used for @var{filename}, whereas
502 @var{src_cache} specifies the cache mode for reading backing files.
504 There are two different modes in which @code{rebase} can operate:
507 This is the default mode and performs a real rebase operation. The new backing
508 file may differ from the old one and qemu-img rebase will take care of keeping
509 the guest-visible content of @var{filename} unchanged.
511 In order to achieve this, any clusters that differ between @var{backing_file}
512 and the old backing file of @var{filename} are merged into @var{filename}
513 before actually changing the backing file.
515 Note that the safe mode is an expensive operation, comparable to converting
516 an image. It only works if the old backing file still exists.
519 qemu-img uses the unsafe mode if @code{-u} is specified. In this mode, only the
520 backing file name and format of @var{filename} is changed without any checks
521 on the file contents. The user must take care of specifying the correct new
522 backing file, or the guest-visible content of the image will be corrupted.
524 This mode is useful for renaming or moving the backing file to somewhere else.
525 It can be used without an accessible old backing file, i.e. you can use it to
526 fix an image whose backing file has already been moved/renamed.
529 You can use @code{rebase} to perform a ``diff'' operation on two
530 disk images. This can be useful when you have copied or cloned
531 a guest, and you want to get back to a thin image on top of a
532 template or base image.
534 Say that @code{base.img} has been cloned as @code{modified.img} by
535 copying it, and that the @code{modified.img} guest has run so there
536 are now some changes compared to @code{base.img}. To construct a thin
537 image called @code{diff.qcow2} that contains just the differences, do:
540 qemu-img create -f qcow2 -b modified.img diff.qcow2
541 qemu-img rebase -b base.img diff.qcow2
544 At this point, @code{modified.img} can be discarded, since
545 @code{base.img + diff.qcow2} contains the same information.
547 @item resize [--shrink] [--preallocation=@var{prealloc}] @var{filename} [+ | -]@var{size}
549 Change the disk image as if it had been created with @var{size}.
551 Before using this command to shrink a disk image, you MUST use file system and
552 partitioning tools inside the VM to reduce allocated file systems and partition
553 sizes accordingly. Failure to do so will result in data loss!
555 When shrinking images, the @code{--shrink} option must be given. This informs
556 qemu-img that the user acknowledges all loss of data beyond the truncated
559 After using this command to grow a disk image, you must use file system and
560 partitioning tools inside the VM to actually begin using the new space on the
563 When growing an image, the @code{--preallocation} option may be used to specify
564 how the additional image area should be allocated on the host. See the format
565 description in the @code{NOTES} section which values are allowed. Using this
566 option may result in slightly more data being allocated than necessary.
568 @item amend [-p] [-f @var{fmt}] [-t @var{cache}] -o @var{options} @var{filename}
570 Amends the image format specific @var{options} for the image file
571 @var{filename}. Not all file formats support this operation.
577 Supported image file formats:
582 Raw disk image format (default). This format has the advantage of
583 being simple and easily exportable to all other emulators. If your
584 file system supports @emph{holes} (for example in ext2 or ext3 on
585 Linux or NTFS on Windows), then only the written sectors will reserve
586 space. Use @code{qemu-img info} to know the real size used by the
587 image or @code{ls -ls} on Unix/Linux.
592 Preallocation mode (allowed values: @code{off}, @code{falloc}, @code{full}).
593 @code{falloc} mode preallocates space for image by calling posix_fallocate().
594 @code{full} mode preallocates space for image by writing zeros to underlying
599 QEMU image format, the most versatile format. Use it to have smaller
600 images (useful if your filesystem does not supports holes, for example
601 on Windows), optional AES encryption, zlib based compression and
602 support of multiple VM snapshots.
607 Determines the qcow2 version to use. @code{compat=0.10} uses the
608 traditional image format that can be read by any QEMU since 0.10.
609 @code{compat=1.1} enables image format extensions that only QEMU 1.1 and
610 newer understand (this is the default). Amongst others, this includes zero
611 clusters, which allow efficient copy-on-read for sparse images.
614 File name of a base image (see @option{create} subcommand)
616 Image format of the base image
618 If this option is set to @code{on}, the image is encrypted with 128-bit AES-CBC.
620 The use of encryption in qcow and qcow2 images is considered to be flawed by
621 modern cryptography standards, suffering from a number of design problems:
625 The AES-CBC cipher is used with predictable initialization vectors based
626 on the sector number. This makes it vulnerable to chosen plaintext attacks
627 which can reveal the existence of encrypted data.
629 The user passphrase is directly used as the encryption key. A poorly
630 chosen or short passphrase will compromise the security of the encryption.
632 In the event of the passphrase being compromised there is no way to
633 change the passphrase to protect data in any qcow images. The files must
634 be cloned, using a different encryption passphrase in the new file. The
635 original file must then be securely erased using a program like shred,
636 though even this is ineffective with many modern storage technologies.
638 Initialization vectors used to encrypt sectors are based on the
639 guest virtual sector number, instead of the host physical sector. When
640 a disk image has multiple internal snapshots this means that data in
641 multiple physical sectors is encrypted with the same initialization
642 vector. With the CBC mode, this opens the possibility of watermarking
643 attacks if the attack can collect multiple sectors encrypted with the
644 same IV and some predictable data. Having multiple qcow2 images with
645 the same passphrase also exposes this weakness since the passphrase
646 is directly used as the key.
649 Use of qcow / qcow2 encryption is thus strongly discouraged. Users are
650 recommended to use an alternative encryption technology such as the
651 Linux dm-crypt / LUKS system.
654 Changes the qcow2 cluster size (must be between 512 and 2M). Smaller cluster
655 sizes can improve the image file size whereas larger cluster sizes generally
656 provide better performance.
659 Preallocation mode (allowed values: @code{off}, @code{metadata}, @code{falloc},
660 @code{full}). An image with preallocated metadata is initially larger but can
661 improve performance when the image needs to grow. @code{falloc} and @code{full}
662 preallocations are like the same options of @code{raw} format, but sets up
666 If this option is set to @code{on}, reference count updates are postponed with
667 the goal of avoiding metadata I/O and improving performance. This is
668 particularly interesting with @option{cache=writethrough} which doesn't batch
669 metadata updates. The tradeoff is that after a host crash, the reference count
670 tables must be rebuilt, i.e. on the next open an (automatic) @code{qemu-img
671 check -r all} is required, which may take some time.
673 This option can only be enabled if @code{compat=1.1} is specified.
676 If this option is set to @code{on}, it will turn off COW of the file. It's only
677 valid on btrfs, no effect on other file systems.
679 Btrfs has low performance when hosting a VM image file, even more when the guest
680 on the VM also using btrfs as file system. Turning off COW is a way to mitigate
681 this bad performance. Generally there are two ways to turn off COW on btrfs:
682 a) Disable it by mounting with nodatacow, then all newly created files will be
683 NOCOW. b) For an empty file, add the NOCOW file attribute. That's what this option
686 Note: this option is only valid to new or empty files. If there is an existing
687 file which is COW and has data blocks already, it couldn't be changed to NOCOW
688 by setting @code{nocow=on}. One can issue @code{lsattr filename} to check if
689 the NOCOW flag is set or not (Capital 'C' is NOCOW flag).
694 QEMU also supports various other image file formats for compatibility with
695 older QEMU versions or other hypervisors, including VMDK, VDI, VHD (vpc), VHDX,
696 qcow1 and QED. For a full list of supported formats see @code{qemu-img --help}.
697 For a more detailed description of these formats, see the QEMU Emulation User
700 The main purpose of the block drivers for these formats is image conversion.
701 For running VMs, it is recommended to convert the disk images to either raw or
702 qcow2 in order to achieve good performance.
708 @setfilename qemu-img
709 @settitle QEMU disk image utility
712 The HTML documentation of QEMU for more precise information and Linux
713 user mode emulator invocation.