使用Qemu-img管理虚拟机磁盘镜像（创建虚拟机，虚拟机快照）

一台虚拟机的核心就是一个磁盘镜像，这个镜像可以理解成虚拟机的磁盘，里面有虚拟机的操作系统和驱动等重要文件。本文主要介绍创建虚拟机的一般过程。

创建虚拟机镜像

要在一台host上跑起一个虚拟机一般需要两个步骤：

第一步：创建虚拟机镜像

<strong>qemu-img create</strong> -f raw /images/vm1.raw 8G

1	<strong>qemu-img create</strong> -f raw /images/vm1.raw 8G

qmeu-img创建的镜像是一个稀疏文件，也就是说刚创建出来的文件并没有8G，它会随着数据的增多慢慢增加，直到8G

第二步：启动虚拟机

<strong>kvm</strong> /imges/vm1.raw

1	<strong>kvm</strong> /imges/vm1.raw

运行结果: 因为镜像里面没有任何内容，所以提示找不到可引导设备。

使用qemu-img管理镜像

qemu-img基本命令

上节介绍了使用qemu-img创建镜像，这一节将会介绍qemu-img在镜像管理上的强大功能。

qemu-img有很多命令，包括下面常用的，当然qemu-img -h你懂得。

info: 查看镜像的信息

create: 创建镜像
check: 检查镜像
convert: 转化镜像的格式，（raw，qcow ……）
snapshot: 管理镜像的快照
rebase: 在已有的镜像的基础上创建新的镜像
resize: 增加或减小镜像大小

创建镜像

<strong>qemu-img create</strong> -f &lt;<span style="font-size:12px;font-family:'Courier New';color:#0000ff;line-height:1.5;">fmt</span>&gt; -o &lt;options&gt; &lt;fname&gt; &lt;size&gt;

				1

						<strong>qemu-img create</strong> -f &lt;<span style="font-size:12px;font-family:'Courier New';color:#0000ff;line-height:1.5;">fmt</span>&gt; -o &lt;options&gt; &lt;fname&gt; &lt;size&gt;

举例：

<strong>qemu-img create</strong> -f raw -o size=4G /images/vm2.raw

1	<strong>qemu-img create</strong> -f raw -o size=4G /images/vm2.raw

<span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">hzgatt@hzgatt:~/</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"><span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">images$</span> <strong>ll</strong> total </span><span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">0</span>-rw-r--r-- <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">1</span> hzgatt hzgatt <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">4</span>.0G  6月 <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">29</span> <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">14</span>:<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">11</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> vm2.raw<span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">hzgatt@hzgatt:</span></span><span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">~/images$</span> <strong>ll -</strong><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"><strong>s</strong> total </span><span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">0</span><span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">0</span> -rw-r--r-- <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">1</span> hzgatt hzgatt <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">4</span>.0G  6月 <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">29</span> <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">14</span>:<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">11</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> vm2.raw</span>

hzgatt@hzgatt:~/images$ ll total 0-rw-r--r-- 1 hzgatt hzgatt 4.0G 6月 29 14:11 vm2.rawhzgatt@hzgatt:~/images$ ll -s total 00 -rw-r--r-- 1 hzgatt hzgatt 4.0G 6月 29 14:11 vm2.raw

<span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">hzgatt@hzgatt:~/images$</span> <strong>qemu-img <span style="font-size:12px;font-family:'Courier New';color:#0000ff;line-height:1.5;">info</span></strong><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"><strong> vm2.raw</strong> 
image: vm2.raw</span><span style="font-size:12px;font-family:'Courier New';color:#0000ff;line-height:1.5;">file</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> format: raw
virtual size: </span><span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">4</span>.0G (<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">4294967296</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> bytes)
disk size: </span><span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">0</span>

hzgatt@hzgatt:~/images$ qemu-img info vm2.raw

image: vm2.rawfile format: raw

virtual size: 4.0G (4294967296 bytes)

disk size: 0

虽然ls中看到文件的大小是4G，但是实际上磁盘大小是0。这就是稀疏文件

转化

将一个镜像文件转化为另外一种格式，qemu-img支持的格式可以看qemu-img -h最后一行。

Supported formats: vvfat vpc vmdk vdi sheepdog rbd raw host_cdrom host_floppy host_device <span style="font-size:12px;font-family:'Courier New';color:#0000ff;line-height:1.5;">file</span> qed qcow2 qcow parallels nbd dmg tftp ftps <span style="font-size:12px;font-family:'Courier New';color:#0000ff;line-height:1.5;">ftp</span> https http cow cloop bochs blkverify blkdebug

Supported formats: vvfat vpc vmdk vdi sheepdog rbd raw host_cdrom host_floppy host_device file qed qcow2 qcow parallels nbd dmg tftp ftps ftp https http cow cloop bochs blkverify blkdebug

转化命令：

<strong>qemu-img convert</strong> <strong>-c</strong> -f fmt <strong>-O</strong> out_fmt <strong>-o</strong> options <strong>fname out_fname</strong>

1	<strong>qemu-img convert</strong> <strong>-c</strong> -f fmt <strong>-O</strong> out_fmt <strong>-o</strong> options <strong>fname out_fname</strong>

-c：采用压缩，只有qcow和qcow2才支持

-f：源镜像的格式，它会自动检测，所以省略之

-O 目标镜像的格式

-o 其他选先

fname：源文件

out_fname:转化后的文件

看例子：

<span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">hzgatt@hzgatt:~/images$</span> <strong>qemu-img convert</strong> -c -O qcow2 vm2.raw vm2.qcow2

1	<span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">hzgatt@hzgatt:~/images$</span> <strong>qemu-img convert</strong> -c -O qcow2 vm2.raw vm2.qcow2

<span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">hzgatt@hzgatt:~/images$</span> <strong>ll -</strong><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"><strong>s</strong> total 136K
   </span><span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">0</span> -rw-r--r-- <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">1</span> hzgatt hzgatt <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">5</span>.0G  6月 <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">29</span> <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">13</span>:<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">55</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> vm1.raw
136K </span>-rw-r--r-- <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">1</span> hzgatt hzgatt 193K  6月 <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">29</span> <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">14</span>:<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">22</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> vm2.qcow2
   </span><span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">0</span> -rw-r--r-- <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">1</span> hzgatt hzgatt <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">4</span>.0G  6月 <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">29</span> <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">14</span>:<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">11</span> vm2.raw

hzgatt@hzgatt:~/images$ ll -s total 136K

0 -rw-r--r-- 1 hzgatt hzgatt 5.0G 6月 29 13:55 vm1.raw

136K -rw-r--r-- 1 hzgatt hzgatt 193K 6月 29 14:22 vm2.qcow2

0 -rw-r--r-- 1 hzgatt hzgatt 4.0G 6月 29 14:11 vm2.raw

<span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">hzgatt@hzgatt:~/images$</span> <strong>qemu-img</strong> <span style="font-size:12px;font-family:'Courier New';color:#0000ff;line-height:1.5;">info</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> vm2.qcow2 
image: vm2.qcow2</span><span style="font-size:12px;font-family:'Courier New';color:#0000ff;line-height:1.5;">file</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> format: qcow2
virtual size: </span><span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">4</span>.0G (<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">4294967296</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> bytes)
disk size: 136K
cluster_size: </span><span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">65536</span>

hzgatt@hzgatt:~/images$ qemu-img info vm2.qcow2

image: vm2.qcow2file format: qcow2

disk size: 136K

cluster_size: 65536

如果想看要转化的格式支持的-o选项有哪些，可以在命令末尾加上 -o ？

<span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;"><A href="mailto:hzgatt@hzgatt:~/images$2>hzgatt@hzgatt:~/images$</a></span> <strong>qemu-img convert</strong> -c -O qcow2 vm2.raw vm2.qcow2<strong> -o ?</strong><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> Supported options:
size             Virtual disk size
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)</span>

<A href="mailto:hzgatt@hzgatt:~/images$2>hzgatt@hzgatt:~/images$</a> qemu-img convert -c -O qcow2 vm2.raw vm2.qcow2 -o ? Supported options:

size Virtual disk size

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)

增加减少镜像大小

注意：只有raw格式的镜像才可以改变大小

<span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">hzgatt@hzgatt:~/images$</span> <strong>qemu-img resize</strong> vm2.raw <strong>+2GB</strong>

1	<span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">hzgatt@hzgatt:~/images$</span> <strong>qemu-img resize</strong> vm2.raw <strong>+2GB</strong>

<strong><A href="mailto:hzgatt@hzgatt:~/images$2>hzgatt@hzgatt:~/images$</a></strong> ll -<span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;">s
total 136K
   </span><span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">0</span> -rw-r--r-- <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">1</span> hzgatt hzgatt <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">5</span>.0G  6月 <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">29</span> <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">13</span>:<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">55</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> vm1.raw
136K </span>-rw-r--r-- <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">1</span> hzgatt hzgatt 193K  6月 <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">29</span> <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">14</span>:<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">22</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> vm2.qcow2
   </span><span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">0</span> -rw-r--r-- <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">1</span> hzgatt hzgatt <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">6</span>.0G  6月 <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">29</span> <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">14</span>:<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">28</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> vm2.raw
hzgatt@hzgatt:</span>~/images$ qemu-img <span style="font-size:12px;font-family:'Courier New';color:#0000ff;line-height:1.5;">info</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> vm2.raw 
image: vm2.raw</span><span style="font-size:12px;font-family:'Courier New';color:#0000ff;line-height:1.5;">file</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> format: raw
virtual size: </span><span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">6</span>.0G (<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">6442450944</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> bytes)
disk size: </span><span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">0</span>

<A href="mailto:hzgatt@hzgatt:~/images$2>hzgatt@hzgatt:~/images$</a> ll -s

total 136K

0 -rw-r--r-- 1 hzgatt hzgatt 6.0G 6月 29 14:28 vm2.raw

hzgatt@hzgatt:~/images$ qemu-img info vm2.raw

virtual size: 6.0G (6442450944 bytes)

disk size: 0

快照

查看快照

<strong>qemu-img snapshot -l</strong> /images/vm2.qcow2

1	<strong>qemu-img snapshot -l</strong> /images/vm2.qcow2

注意：只有qcow2才支持快照

打快照

<strong>qemu-img snapshot -c</strong> booting vm2.qcow2

1	<strong>qemu-img snapshot -c</strong> booting vm2.qcow2

举例：

<span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">hzgatt@hzgatt:~/images$</span> <strong>qemu-img snapshot</strong> -<span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;">c booting vm2.qcow2 <span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">hzgatt@hzgatt:</span></span><span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">~/images$</span> <strong>qemu-img snapshot</strong> -<span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;">l vm2.qcow2 
Snapshot list:
ID        TAG                 VM SIZE                DATE       VM CLOCK</span><span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">1</span>         booting                   <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">0</span> <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">2012</span>-<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">06</span>-<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">29</span> <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">14</span>:<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">35</span>:<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">04</span>   <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">00</span>:<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">00</span>:<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">00.000</span>

hzgatt@hzgatt:~/images$ qemu-img snapshot -c booting vm2.qcow2 hzgatt@hzgatt:~/images$ qemu-img snapshot -l vm2.qcow2

Snapshot list:

ID TAG VM SIZE DATE VM CLOCK1 booting 0 2012-06-29 14:35:04 00:00:00.000

从快照恢复：

<strong>qemu-img snapshot</strong> <strong>-a</strong> <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">1</span> /images/vm2.qcow2

1	<strong>qemu-img snapshot</strong> <strong>-a</strong> <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">1</span> /images/vm2.qcow2

然后从kvm启动这个虚拟机，会发现虚拟机又在打快照时的状态了

删除快照：

<strong>qemu-img snapshot -d</strong> <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">2</span> /images/vm2.qcow

1	<strong>qemu-img snapshot -d</strong> <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">2</span> /images/vm2.qcow

使用派生镜像(qcow2)

当创建的虚拟机越来越多，并且你发现好多虚拟机都是同一个操作系统，它们的区别就是安装的软件不大一样，那么你肯定会希望把他们公共的部分提取出来，只保存那些与公共部分不同的东西，这样镜像大小下去了，空间变多了，管理也方便了。派生镜像就是用来干这事的！

首先看一个原始镜像

<span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">hzgatt@hzgatt:~/images$</span> <strong>qemu-img <span style="font-size:12px;font-family:'Courier New';color:#0000ff;line-height:1.5;">info</span></strong><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> vm3_base.raw 
image: vm3_base.raw</span><span style="font-size:12px;font-family:'Courier New';color:#0000ff;line-height:1.5;">file</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> format: raw
virtual size: </span><span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">2</span>.0G (<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">2147483648</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> bytes)
disk size: </span><span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">2</span>.0G

image: vm3_base.rawfile format: raw

virtual size: 2.0G (2147483648 bytes)

disk size: 2.0G

现在我们新建一个镜像，但是派生自它

<span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">hzgatt@hzgatt:~/images$</span> <strong>qemu-img create</strong> <strong>-f qcow2 vm3_5.qcow2 -o backing_file=</strong><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"><strong>vm3_base.raw 5G</strong> Formatting </span><span style="font-size:12px;font-family:'Courier New';color:#800000;line-height:1.5;">'</span><span style="font-size:12px;font-family:'Courier New';color:#800000;line-height:1.5;">vm3_5.qcow2</span><span style="font-size:12px;font-family:'Courier New';color:#800000;line-height:1.5;">'</span>, <span style="font-size:12px;font-family:'Courier New';color:#0000ff;line-height:1.5;">fmt</span>=qcow2 size=<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">5368709120</span> backing_file=<span style="font-size:12px;font-family:'Courier New';color:#800000;line-height:1.5;">'</span><span style="font-size:12px;font-family:'Courier New';color:#800000;line-height:1.5;">vm3_base.raw</span><span style="font-size:12px;font-family:'Courier New';color:#800000;line-height:1.5;">'</span> encryption=off cluster_size=<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">65536</span>

hzgatt@hzgatt:~/images$ qemu-img create -f qcow2 vm3_5.qcow2 -o backing_file=vm3_base.raw 5G Formatting 'vm3_5.qcow2', fmt=qcow2 size=5368709120 backing_file='vm3_base.raw' encryption=off cluster_size=65536

<span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">hzgatt@hzgatt:~/</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"><span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">images$</span> <strong>ll</strong></span>-rw-r--r-- <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">1</span> hzgatt hzgatt 193K  6月 <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">29</span> <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">15</span>:<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">00</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> vm3_5.qcow2</span>-rw-r--r-- <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">1</span> hzgatt hzgatt <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">2</span>.0G  6月 <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">29</span> <span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">14</span>:<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">51</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> vm3_base.raw<span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;"> </span></span>

hzgatt@hzgatt:~/images$ ll-rw-r--r-- 1 hzgatt hzgatt 193K 6月 29 15:00 vm3_5.qcow2-rw-r--r-- 1 hzgatt hzgatt 2.0G 6月 29 14:51 vm3_base.raw

<span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;"><A href="mailto:hzgatt@hzgatt:~/images$2>hzgatt@hzgatt:~/images$</a></span> <strong>qemu-img <span style="font-size:12px;font-family:'Courier New';color:#0000ff;line-height:1.5;">info</span></strong><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"><strong> vm3_5.qcow2</strong> 
image: vm3_5.qcow2</span><span style="font-size:12px;font-family:'Courier New';color:#0000ff;line-height:1.5;">file</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> format: qcow2
virtual size: </span><span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">5</span>.0G (<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">5368709120</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> bytes)
disk size: 136K
cluster_size: </span><span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">65536</span><span style="font-size:12px;font-family:'Courier New';line-height:1.5;background-color:#ccffcc;"><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> backing </span><span style="font-size:12px;font-family:'Courier New';color:#0000ff;line-height:1.5;">file</span>: vm3_base.raw (actual path: vm3_base.raw)</span>

<A href="mailto:hzgatt@hzgatt:~/images$2>hzgatt@hzgatt:~/images$</a> qemu-img info vm3_5.qcow2

image: vm3_5.qcow2file format: qcow2

virtual size: 5.0G (5368709120 bytes)

disk size: 136K

cluster_size: 65536 backing file: vm3_base.raw (actual path: vm3_base.raw)

^_^，这个镜像才136K，够省了吧。DRY永远的真理啊！

现在我们在vm3_5.qcow2上打了很多安全补丁，然后发现我又想在vm3_5.qcow2上派生新的虚拟机，o(∩∩)o...哈哈，这下怎么办呢？

<span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">hzgatt@hzgatt:~/images$</span> <strong>qemu-img convert</strong> -O raw vm3_5.qcow2 vm3_base2.raw

1	<span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">hzgatt@hzgatt:~/images$</span> <strong>qemu-img convert</strong> -O raw vm3_5.qcow2 vm3_base2.raw

<span style="font-size:12px;font-family:'Courier New';text-decoration:underline;line-height:1.5;">hzgatt@hzgatt:~/images$</span> <strong>qemu-img <span style="font-size:12px;font-family:'Courier New';color:#0000ff;line-height:1.5;">info</span></strong><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> vm3_base2.raw 
image: vm3_base2.raw</span><span style="font-size:12px;font-family:'Courier New';color:#0000ff;line-height:1.5;">file</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> format: raw
virtual size: </span><span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">5</span>.0G (<span style="font-size:12px;font-family:'Courier New';color:#800080;line-height:1.5;">5368709120</span><span style="font-size:12px;font-family:'Courier New';color:#000000;line-height:1.5;"> bytes)
disk size: 592M</span>

image: vm3_base2.rawfile format: raw

disk size: 592M

这个转化将会将vm3_5和base合并，生成新的vm3_base2.raw，然后你就可以继续无穷无尽的派生之旅了！

数据恢复实验室 Data Recovery Laboratory

力求做到最好的数据恢复效果，降低数据丢失带来的损失，为您的数据安全保驾护航。