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| qemu-img -h <br /> usage: qemu-img command \[command options\] <br /> QEMU disk image utility <br /> <br /> Command syntax: <br /> check \[-f fmt\] \[-r \[leaks | all\]\] filename <br /> **create** \[-f fmt\] \[-o options\] filename \[size\] <br />
qemu-img create -f raw ./images/cirros.raw 1G
>Formatting './images/cirros.raw', fmt=raw size=1073741824
ll -h
>-rw-r--r-- 1 root root 1.0G Jul 13 21:53 cirros.raw
qemu-system-x86_64 /images/cirros.raw
>backing_file
qemu-img create -f qcow2 cirros_backing.qcow2 -o backing_file=cirros.raw 1G
ll -h
>-rw-r--r-- 1 root root 193K Jul 13 22:28 cirros_backing.qcow2
qemu-img info cirros_backing.qcow2
>image: cirros_backing.qcow2
>file format: qcow2
>virtual size: 1.0G (1073741824 bytes)
>disk size: 196K
>cluster_size: 65536
>backing file: cirros.raw
>使用backing_file创建的模板可以convert成raw格式，包含整个模板文件
>这个convert将cirros_backing.qcow2和cirros.raw合并，生成新的raw格式模板
qemu-img convert -O raw cirros_backing.qcow2 cirros_backing.raw
qemu-img info cirros_backing.raw
>image: cirros_backing.raw
>file format: raw
>virtual size: 1.0G (1073741824 bytes)
>disk size: 0
|
commit [-f fmt] [-t cache] filename
convert [-c] [-p] [-f fmt] [-t cache] [-O output_fmt] [-o options] [-s snapshot_name] [-S sparse_size] filename [filename2 […]] output_filename
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| qemu-img convert -c -f raw -O qcow2 cirros.raw cirros.qcow2
ll -h
>-rw-r--r-- 1 root root 193K Jul 13 21:58 cirros.qcow2
>-rw-r--r-- 1 root root 1.0G Jul 13 21:53 cirros.raw
qemu-img convert -c -f raw -O qcow2 cirros.raw cirros.qcow2 -o ?
>Supported options:
>size Virtual disk size
>compat Compatibility level (0.10 or 1.1)
>backing_file File name of a base image
>backing_fmt Image format of the base image
>encryption Encrypt the image
>cluster_size qcow2 cluster size
>preallocation Preallocation mode (allowed values: off, metadata)
>lazy_refcounts Postpone refcount updates
|
info [-f fmt] [–output=ofmt] [–backing-chain] filename
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| qemu-img info cirros.raw
>image: cirros.raw
>file format: raw
>virtual size: 1.0G (1073741824 bytes)
>disk size: 0
>虽然ll中看到文件的大小是1G，但是实际上磁盘大小是0。这就是稀疏文件
qemu-img info cirros.qcow2
>image: cirros.qcow2
>file format: qcow2
>virtual size: 1.0G (1073741824 bytes)
>disk size: 136K
>cluster_size: 65536
|
| snapshot [-l |
-a snapshot |
-c snapshot |
-d snapshot] filename
|
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| >只有qcow2才支持快照
qemu-img snapshot -l cirros.qcow2
qemu-img snapshot -c tag1 cirros.qcow2
qemu-img snapshot -c tag2 cirros.qcow2
qemu-img snapshot -l cirros.qcow2
>Snapshot list:
>ID TAG VM SIZE DATE VM CLOCK
>1 tag1 0 2013-07-13 22:14:31 00:00:00.000
>2 tag2 0 2013-07-13 22:15:31 00:00:00.000
qemu-img snapshot -a 2 cirros.qcow2
qemu-img snapshot -d 1 cirros.qcow2
qemu-img snapshot -l cirros.qcow2
>Snapshot list:
>ID TAG VM SIZE DATE VM CLOCK
>2 tag2 0 2013-07-13 22:15:31 00:00:00.000
|
rebase [-f fmt] [-t cache] [-p] [-u] -b backing_file [-F backing_fmt] filename
resize filename [+ | -]size
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| >只有raw格式的镜像才可以改变大小
qemu-img resize cirros.raw +1GB
>Image resized.
ll -h
>-rw-r--r-- 1 root root 193K Jul 13 21:58 cirros.qcow2
>-rw-r--r-- 1 root root 2.0G Jul 13 22:08 cirros.raw
|
Command parameters:
‘filename’ is a disk image filename
‘fmt’ is the disk image format. It is guessed automatically in most cases
‘cache’ is the cache mode used to write the output disk image, the valid options are: ‘none’, ‘writeback’ (default, except for convert), ‘writethrough’, ‘directsync’ and ‘unsafe’ (default for convert)
‘size’ is the disk image size in bytes. Optional suffixes ‘k’ or ‘K’ (kilobyte, 1024), ‘M’ (megabyte, 1024k), ‘G’ (gigabyte, 1024M) and T (terabyte, 1024G) are supported. ‘b’ is ignored.
‘output_filename’ is the destination disk image filename
‘output_fmt’ is the destination format
‘options’ is a comma separated list of format specific options in a name=value format. Use -o ? for an overview of the options supported by the used format
‘-c’ indicates that target image must be compressed (qcow format only)
‘-u’ enables unsafe rebasing. It is assumed that old and new backing file match exactly. The image doesn’t need a working backing file before rebasing in this case (useful for renaming the backing file)
‘-h’ with or without a command shows this help and lists the supported formats
‘-p’ show progress of command (only certain commands)
‘-S’ indicates the consecutive number of bytes that must contain only zeros for qemu-img to create a sparse image during conversion
‘–output’ takes the format in which the output must be done (human or json)
Parameters to check subcommand:
‘-r’ tries to repair any inconsistencies that are found during the check. ‘-r leaks’ repairs only cluster leaks, whereas ‘-r all’ fixes all kinds of errors, with a higher risk of choosing the wrong fix or hiding corruption that has already occurred.
Parameters to snapshot subcommand:
‘snapshot’ is the name of the snapshot to create, apply or delete
‘-a’ applies a snapshot (revert disk to saved state)
‘-c’ creates a snapshot
‘-d’ deletes a snapshot
‘-l’ lists all snapshots in the given image
Supported formats: vvfat vpc vmdk vdi sheepdog raw host_cdrom host_floppy host_device file qed qcow2 qcow parallels nbd nbd nbd iscsi dmg tftp ftps ftp https http cow cloop bochs blkverify blkdebug