KVM 快照

Posted 2020-11-19 skyzy

kvm快照

# virsh shutdown kvm1

# qemu-img info /var/lib/libvirt/images/kvm1.img ----raw格式是不支持snapshot功能，所以我们需要转换成象qcow2这种支持snapshot功能的格式（rhel7,cenots7已经默认是qcow2格式了)

image: /var/lib/libvirt/images/kvm1.img

file format: raw

virtual size: 20G (21474836480 bytes)

disk size: 6.5G

# cd /var/lib/libvirt/images/

# qemu-img convert -f raw -O qcow2 kvm1.img kvm1.qcow2.img

----把磁盘格式由raw转换为qcow2

# ll -h kvm1* ----qcow2格式占用空间小

# virsh edit kvm1 ----编辑kvm1虚拟的主配置文件,把raw磁盘换成qcow2磁盘

<disk type=‘file‘ device=‘disk‘>

<driver name=‘qemu‘ type=‘qcow2‘ cache=‘none‘/> ----把type里的row改成qcow2

<source file=‘/var/lib/libvirt/images/kvm1.qcow2.img‘/> ----把路径也改成转换为qcow2格式的文件路径

<target dev=‘vda‘ bus=‘virtio‘/>

<address type=‘pci‘ domain=‘0x0000‘ bus=‘0x00‘ slot=‘0x05‘ function=‘0x0‘/>

</disk>

# virsh define kvm1.xml

# virsh start kvm1 ----再启动,使他生效

# rm -rf /var/lib/libvirt/images/kvm1.img ----可以把原来的raw格式的磁盘文件给删除掉

# virsh help snapshot ----查看和快照操作有关的命令

# virsh snapshot-list kvm1 ----列快照,默认没有

Name Creation Time State

------------------------------------------------------------

# virsh snapshot-create-as --domain kvm1 snap1 --description "my first test snapshot" ----对kvm1创建一个叫snap1的快照

# /var/lib/libvirt/qemu/snapshot/kvm1/ ----默认快照的保存位置

# virsh snapshot-list kvm1

Name Creation Time State

------------------------------------------------------------

snap1 2017-04-21 09:56:47 +0800 running

查看帮助

# virsh help snapshot

查看快照配置

# virsh snapshot-current kvm1

恢复快照

# virsh snapshot-revert kvm1 snap1

删除快照

# virsh snapshot-delete kvm1 snap1

--恢复快照时报错:error: revert requires force: Target controller type ide does not match source usb

表示kvm不能在线恢复，需要关闭虚拟机，再恢复快照。如果你要在线恢复快照，需要加一个--force的参数

写法如:

# virsh snapshot-revert kvm1 snap1 --force

恢复快照的时间较长，恢复完后，键盘操作会有些问题，可以把它重启一下

# virsh destroy kvm1

# virsh start kvm1

==========================

在rhel7和centos7下使用快照非常方便，速度也快很多

主要记住下面几条命令就ok

# virsh snapshot-list kvm1

# virsh snapshot-create-as --domain kvm1 snap1 --description "my first test snapshot"

# virsh snapshot-revert kvm1 snap1

# virsh snapshot-delete kvm1 snap1