kvm虚拟机快照备份

kvm虚拟机默认使用raw格式的镜像格式，性能最好，速度最快，它的缺点就是不支持一些新的功能，如支持镜像,zlib磁盘压缩,AES加密等。
要使用镜像功能，磁盘格式必须为qcow2。下面开始kvm虚拟机快照备份的过程。

本文出自：http://koumm.blog.51cto.com

进一步的学习参考：kvm+libvirt虚拟机快照浅析 http://itxx.sinaapp.com/blog/content/130

1. 查看现有磁盘镜像格式与转换

(1) 查看磁盘格式

# qemu-img info test01.img

raw格式需要转换成qcow2

(2) 关闭虚拟机并转换磁盘

# virsh shutdown oeltest01

(3) 转换磁盘格式

# qemu-img convert -f raw -O qcow2 test01.img test01.qcow2

-f 源镜像的格式
-O 目标镜像的格式

查看转换后的格式，已经转换成了qcow2, 这里是拷贝一份，并将格式转成qcow2

# qemu-img info test01.qcow2

2. 修改虚拟机配置文件

修改磁盘格式，与新qcow2格式的磁盘。

3. 对虚拟机进行快照管理

(1) 对oeltest01虚拟机创建快照

也可以virsh snapshot-create as oeltest01 snap1 创建后个快照别名。

(2) 查看虚拟机镜像快照的版本

(3) 查看当前虚拟机镜像快照的版本

可以看到为当前最新的快照版本。

[root@node1 data]#
[root@node1 data]# virsh snapshot-current oeltest01
<domainsnapshot>
  <name>1378579737</name>
  <state>shutoff</state>
  <creationTime>1378579737</creationTime>
  <memory snapshot='no'/>
  <disks>
    <disk name='hda' snapshot='internal'/>
    <disk name='hdc' snapshot='no'/>
  </disks>
  <domain type='kvm'>
    <name>oeltest01</name>
    <uuid>8f2bb4a7-c7ed-32aa-3676-9fb05923269d</uuid>
    <memory unit='KiB'>524288</memory>
    <currentMemory unit='KiB'>524288</currentMemory>
    <vcpu placement='static'>1</vcpu>
    <os>
      <type arch='x86_64' machine='rhel6.4.0'>hvm</type>
      <boot dev='hd'/>
    </os>
    <features>
      <acpi/>
      <apic/>
      <pae/>
    </features>
    <clock offset='localtime'/>
    <on_poweroff>destroy</on_poweroff>
    <on_reboot>restart</on_reboot>
    <on_crash>restart</on_crash>
    <devices>
      <emulator>/usr/libexec/qemu-kvm</emulator>
      <disk type='file' device='disk'>
        <driver name='qemu' type='qcow2' cache='none'/>
        <source file='/data/test01.qcow2'/>
        <target dev='hda' bus='ide'/>
        <address type='drive' controller='0' bus='0' target='0' unit='0'/>
      </disk>
      <disk type='block' device='cdrom'>
        <driver name='qemu' type='raw'/>
        <target dev='hdc' bus='ide'/>
        <readonly/>
        <address type='drive' controller='0' bus='1' target='0' unit='0'/>
      </disk>
      <controller type='ide' index='0'>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
      </controller>
      <controller type='usb' index='0'/>
      <interface type='bridge'>
        <mac address='52:54:00:82:39:01'/>
        <source bridge='br0'/>
        <model type='virtio'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
      </interface>
      <serial type='pty'>
        <target port='0'/>
      </serial>
      <console type='pty'>
        <target type='serial' port='0'/>
      </console>
      <input type='tablet' bus='usb'/>
      <input type='mouse' bus='ps2'/>
      <graphics type='vnc' port='5910' autoport='no' listen='0.0.0.0'>
        <listen type='address' address='0.0.0.0'/>
      </graphics>
      <video>
        <model type='cirrus' vram='9216' heads='1'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
      </video>
      <memballoon model='virtio'>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
      </memballoon>
    </devices>
  </domain>
</domainsnapshot>