QEMU-IMG(1) QEMU QEMU-IMG(1) (NAME) qemu-img - QEMU (SYNOPSIS) qemu-img [standard options] command [command options] (DESCRIPTION) qemu-img . QEMU . : qemu-img . . (OPTIONS) : -h, --help -V, --version -T, --trace [[enable=]PATTERN][,events=FILE][,file=FILE] (tracing). [enable=]PATTERN PATTERN ( globbing). QEMU backend simple log ftrace . -trace . (trace points) -trace help . events=FILE FILE. ( trace-events-all ) globbing . QEMU backend simple log ftrace . file=FILE FILE. QEMU backend simple . : amend [--object OBJECTDEF] [--image-opts] [-p] [-q] [-f FMT] [-t CACHE] [--force] -o OPTIONS FILENAME bench [-c COUNT] [-d DEPTH] [-f FMT] [--flush-interval=FLUSH_INTERVAL] [-i AIO] [-n] [--no-drain] [-o OFFSET] [--pattern=PATTERN] [-q] [-s BUFFER_SIZE] [-S STEP_SIZE] [-t CACHE] [-w] [-U] FILENAME bitmap (--merge SOURCE | --add | --remove | --clear | --enable | --disable)... [-b SOURCE_FILE [-F SOURCE_FMT]] [-g GRANULARITY] [--object OBJECTDEF] [--image-opts | -f FMT] FILENAME BITMAP check [--object OBJECTDEF] [--image-opts] [-q] [-f FMT] [--output=OFMT] [-r [leaks | all]] [-T SRC_CACHE] [-U] FILENAME commit [--object OBJECTDEF] [--image-opts] [-q] [-f FMT] [-t CACHE] [-b BASE] [-r RATE_LIMIT] [-d] [-p] FILENAME compare [--object OBJECTDEF] [--image-opts] [-f FMT] [-F FMT] [-T SRC_CACHE] [-p] [-q] [-s] [-U] FILENAME1 FILENAME2 convert [--object OBJECTDEF] [--image-opts] [--target-image-opts] [--target-is-zero] [--bitmaps] [-U] [-C] [-c] [-p] [-q] [-n] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-O OUTPUT_FMT] [-B BACKING_FILE [-F BACKING_FMT]] [-o OPTIONS] [-l SNAPSHOT_PARAM] [-S SPARSE_SIZE] [-r RATE_LIMIT] [-m NUM_COROUTINES] [-W] [--salvage] FILENAME [FILENAME2 [...]] OUTPUT_FILENAME create [--object OBJECTDEF] [-q] [-f FMT] [-b BACKING_FILE [-F BACKING_FMT]] [-u] [-o OPTIONS] FILENAME [SIZE] dd [--image-opts] [-U] [-f FMT] [-O OUTPUT_FMT] [bs=BLOCK_SIZE] [count=BLOCKS] [skip=BLOCKS] if=INPUT of=OUTPUT info [--object OBJECTDEF] [--image-opts] [-f FMT] [--output=OFMT] [--backing-chain] [--limits] [-t CACHE] [-U] FILENAME map [--object OBJECTDEF] [--image-opts] [-f FMT] [--start-offset=OFFSET] [--max-length=LEN] [--output=OFMT] [-U] FILENAME measure [--output=OFMT] [-O OUTPUT_FMT] [-o OPTIONS] [--size N | [--object OBJECTDEF] [--image-opts] [-f FMT] [-l SNAPSHOT_PARAM] FILENAME] snapshot [--object OBJECTDEF] [-f FMT | --image-opts] [-U] [-q] [-l | -a SNAPSHOT | -c SNAPSHOT | -d SNAPSHOT] FILENAME rebase [--object OBJECTDEF] [--image-opts] [-U] [-q] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-p] [-u] [-c] -b BACKING_FILE [-F BACKING_FMT] FILENAME resize [--object OBJECTDEF] [--image-opts] [-f FMT] [--preallocation=PREALLOC] [-q] [--shrink] FILENAME [+ | -]SIZE : FILENAME . FMT . . . SIZE . k K ( ) M ( 1024k) G ( 1024M) T ( 1024G) . b . OUTPUT_FILENAME . OUTPUT_FMT . OPTIONS name=value . -o help . SNAPSHOT_PARAM 'snapshot.id=[ID],snapshot.name=[NAME]' '[ID_OR_NAME]' . --object OBJECTDEF QEMU . qemu(1) . secret / . --image-opts FILENAME . -f . --target-image-opts () OUTPUT_FILENAME . -O . -n . . --force-share (-U) qemu-img QEMU . ( 'info') . . . --backing-chain . . -c ( qcow/qcow2 vmdk streamOptimized). qcow2 -o compression_type=... ( ). -h . -p ( compare convert rebase). -p SIGUSR1 SIGINFO . -q - ( ). -q -p . -S SIZE qemu-img (sparse) . . k . -t CACHE (cache) () . -drive cache=... . -T SRC_CACHE (cache) () . -drive cache=... . compare: -f -F -s - convert: --bitmaps (persistent bitmaps) -n -m -W . . -C (copy offloading) . NFS iSCSI . -r --salvage I/O . (-q) . . --target-is-zero . . -n . dd: bs=BLOCK_SIZE count=BLOCKS if=INPUT of=OUTPUT skip=BLOCKS snapshot: snapshot snapshot -a snapshot ( ) -c snapshot -d snapshot -l snapshot ( ) : amend [--object OBJECTDEF] [--image-opts] [-p] [-q] [-f FMT] [-t CACHE] [--force] -o OPTIONS FILENAME (OPTIONS) FILENAME . . (backing chain) qemu-img rebase . --force . -f luks . bench [-c COUNT] [-d DEPTH] [-f FMT] [--flush-interval=FLUSH_INTERVAL] [-i AIO] [-n] [--no-drain] [-o OFFSET] [--pattern=PATTERN] [-q] [-s BUFFER_SIZE] [-S STEP_SIZE] [-t CACHE] [-w] [-U] FILENAME / (I/O) . -w . COUNT I/O BUFFER_SIZE DEPTH . OFFSET STEP_SIZE . STEP_SIZE BUFFER_SIZE . FLUSH_INTERVAL FLUSH_INTERVAL flush . --no-drain flush . -i AIO backend AIO : threads native io_uring. -n backend AIO . -t none -t directsync . . PATTERN . bitmap (--merge SOURCE | --add | --remove | --remove-all | --clear | --enable | --disable)... [-b SOURCE_FILE [-F SOURCE_FMT]] [-g GRANULARITY] [--object OBJECTDEF] [--image-opts | -f FMT] FILENAME [BITMAP] (persistent bitmaps) FILENAME . BITMAP --remove-all BITMAP . : --add BITMAP . --remove BITMAP. --remove-all . --clear BITMAP. --enable BITMAP . --disable BITMAP . --merge SOURCE BITMAP. -g GRANULARITY --add -b -F SOURCE --merge . qemu-img info . check [--object OBJECTDEF] [--image-opts] [-q] [-f FMT] [--output=OFMT] [-r [leaks | all]] [-T SRC_CACHE] [-U] FILENAME FILENAME . OFMT human json . JSON QAPI ImageCheck . -r qemu-img . -r leaks -r all . qcow2 qed parallels vhdx vmdk vdi . check 0 . . check : 0 () 1 2 3 63 -r ( ) . -r all 0 . commit [--object OBJECTDEF] [--image-opts] [-q] [-f FMT] [-t CACHE] [-b BASE] [-r RATE_LIMIT] [-d] [-p] FILENAME FILENAME (commit) . snapshot snapshot . snapshot (truncate) . snapshot commit truncate . FILENAME . FILENAME -d FILENAME . FILENAME BASE ( FILENAME ). BASE ( FILENAME ) . commit BASE . -b -d ( ). commit -r . compare [--object OBJECTDEF] [--image-opts] [-f FMT] [-F FMT] [-T SRC_CACHE] [-p] [-q] [-s] [-U] FILENAME1 FILENAME2 . . -f ( FILENAME1) / -F ( FILENAME2) . / . . -s (Strict mode) . compare ..sp compare . . Strict . compare 0 1 . . compare : 0 ( ) 1 2 3 4 convert [--object OBJECTDEF] [--image-opts] [--target-image-opts] [--target-is-zero] [--bitmaps [--skip-broken-bitmaps]] [-U] [-C] [-c] [-p] [-q] [-n] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-O OUTPUT_FMT] [-b BACKING_FILE [-F BACKING_FMT]] [-o OPTIONS] [-l SNAPSHOT_PARAM] [-S SPARSE_SIZE] [-r RATE_LIMIT] [-m NUM_COROUTINES] [-W] FILENAME [FILENAME2 [...]] OUTPUT_FILENAME FILENAME SNAPSHOT_PARAM OUTPUT_FMT OUTPUT_FILENAME . ( -c) ( -o) . qcow qcow2 . . qcow : . SPARSE_SIZE ( 4k) qemu-img (sparse) . SPARSE_SIZE 0 . BACKING_FILE (copy-on-write) BACKING_FILE ( BACKING_FMT) . OUTPUT_FILENAME . -n . rbd qemu-img . -W . . . NUM_COROUTINES (coroutine) ( 8 ). --bitmaps . --skip-broken-bitmaps . create [-f FMT] [-o FMT_OPTS] [-b BACKING_FILE [-B BACKING_FMT]] [-u] [-q] [--object OBJDEF] FILE [SIZE] FILE SIZE FMT . FMT_OPTS . BACKING_FILE BACKING_FILE . . BACKING_FILE commit ( qemu-img commit) . FILE . . -u . . SIZE -o . dd [--image-opts] [-U] [-f FMT] [-O OUTPUT_FMT] [bs=BLOCK_SIZE] [count=BLOCKS] [skip=BLOCKS] if=INPUT of=OUTPUT dd INPUT OUTPUT FMT OUTPUT_FMT . BLOCK_SIZE . count=BLOCKS dd BLOCKS . dd(1) . info [--object OBJECTDEF] [--image-opts] [-f FMT] [--output=OFMT] [--backing-chain] [--limits] [-t CACHE] [-U] FILENAME FILENAME . . . --backing-chain . : base.qcow2 <- snap1.qcow2 <- snap2.qcow2 : qemu-img info --backing-chain snap2.qcow2 OFMT human json. JSON QAPI ImageInfo --backing-chain ImageInfo . --output=human ( ): image file format virtual size disk size ( 0 ) cluster_size encrypted ( ) cleanly shut down dirty qemu no . backing file backing file format .TP Snapshot list . Format specific information . QAPI ImageInfoSpecific* ( ImageInfoSpecificQCow2 qcow2). Block limits / (I/O) QEMU . --limits . map [--object OBJECTDEF] [--image-opts] [-f FMT] [--start-offset=OFFSET] [--max-length=LEN] [--output=OFMT] [-U] FILENAME FILENAME (dump) . FILENAME . . (human) . . qemu-img . () . : Offset Length Mapped to File 0 0x20000 0x50000 /tmp/overlay.qcow2 0x100000 0x10000 0x95380000 /tmp/backing.qcow2 0x20000 (131072) 0 /tmp/overlay.qcow2 ( raw) 0x50000 (327680) . raw human . (newline) . json JSON . start length offset : o data: true false (all-zero) o zero: true o present: true false rebase o depth: 2 FILENAME . JSON offset human . data false offset (preallocated). include/block/block.h QEMU . measure [--output=OFMT] [-O OUTPUT_FMT] [-o OPTIONS] [--size N | [--object OBJECTDEF] [--image-opts] [-f FMT] [-l SNAPSHOT_PARAM] FILENAME] . (logical volumes) SAN LUN . . OFMT human json. JSON QAPI BlockMeasureInfo . N qemu-img create . FILENAME qemu-img convert . OUTPUT_FMT FMT . SNAPSHOT_PARAM . : required size: 524288 fully allocated size: 1074069504 bitmaps size: 0 required size . (compact representation) . fully allocated size . bitmap dirty vmstate . bitmaps size bitmap (guest-visible) bitmap bitmap 0 . snapshot [--object OBJECTDEF] [-f FMT | --image-opts] [-U] [-q] [-l | -a SNAPSHOT | -c SNAPSHOT | -d SNAPSHOT] FILENAME FILENAME. rebase [--object OBJECTDEF] [--image-opts] [-U] [-q] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-p] [-u] [-c] -b BACKING_FILE [-B BACKING_FMT] FILENAME (backing file) . qcow2 qed . BACKING_FILE ( FILENAME ) BACKING_FMT . BACKING_FILE "" ( ) rebase ( ). FILENAME . CACHE FILENAME SRC_CACHE . rebase : (Safe mode) rebase . qemu-img rebase (guest-visible) FILENAME . BACKING_FILE FILENAME FILENAME (merge) . -c ( FILENAME) . . . (Unsafe mode) -u qemu-img . FILENAME . . . . rebase ("diff") . (clone) (thin image) ..sp base.img modified.img modified.img base.img . (thin) diff.qcow2 : qemu-img create -f qcow2 -b modified.img diff.qcow2 qemu-img rebase -b base.img diff.qcow2 modified.img base.img + diff.qcow2 . resize [--object OBJECTDEF] [--image-opts] [-f FMT] [--preallocation=PREALLOC] [-q] [--shrink] FILENAME [+ | -]SIZE SIZE . (shrink) . ! --shrink . qemu-img . . --preallocation . (NOTES) . . (NOTES) : raw (raw) (). . holes ( ext2 ext3 NTFS ) . qemu-img info / ls -ls . : preallocation ( : off falloc full). falloc posix_fallocate() . full . . qcow2 QEMU . ( ) AES zlib zstd . : compat qcow2 . compat=0.10 QEMU 0.10 . compat=1.1 QEMU 1.1 ( ). copy-on-read . backing_file ( create ) backing_fmt compression_type . . -c qemu-img convert compress . zlib zstd. compat=0.10 zlib . encryption on 128 AES-CBC . qcow qcow2 : o AES-CBC (IV) . (chosen plaintext attacks) . o . . o qcow . . shred . o . . CBC IV (watermarking attacks) . qcow2 . qcow / qcow2 . dm-crypt / LUKS . cluster_size qcow2 ( 512 2M ). . preallocation ( : off metadata falloc full). . falloc full raw . lazy_refcounts on I/O . cache=writethrough . (crash) qemu-img check -r all ( ) . compat=1.1 . nocow on COW . btrfs . Btrfs btrfs . COW . COW btrfs : o nodatacow NOCOW o NOCOW . . : . COW nocow=on NOCOW . lsattr filename NOCOW ( 'C' NOCOW ). data_file . qcow2 . : qemu-img create qemu-img . qemu-img amend . data_file_raw on QEMU (raw) . qcow2 raw . qcow2 ( ) raw . raw . qcow2 qcow2 (out-of-band) raw . off QEMU . qcow2 . ( ) qcow2 . data_file . QEMU QEMU VMDK VDI VHD (vpc) VHDX qcow1 QED. qemu-img --help . (block drivers) QEMU . . raw qcow2 . (AUTHORS) Fabrice Bellard (COPYRIGHT) 2026, The QEMU Project Developers 11.1.1 August 28, 2026 QEMU-IMG(1)