KVM创建快照

Bertha 。 2022-11-15 12:53 282阅读 0赞

> 快照可以把虚拟机某个时间点磁盘文件状态保存为一个镜像文件。通过这个镜像文件，可以在以后的任何时间快速恢复虚拟机在当时创建snapshot的状态，这个在使用虚拟机来做测试的时候很有用。

**一、创建快照前提**

*  kvm虚拟机的raw格式磁盘文件不支持快照功能，在创建快照前需要先转换为qcow2格式

# qemu-img info test7.raw
    image: test7.raw
    file format: raw
    virtual size: 150G (161061273600 bytes)
    disk size: 3.4G
    cluster_size: 65536
    Format specific information:
        compat: 1.1
        lazy refcounts: true
    
    # 从raw格式转成qcow2格式
    # qemu-img convert -f raw -O qcow2 test7.raw test7.qcow2

**二、创建虚拟机快照**

*  查看虚拟机快照列表

# virsh snapshot-list test7 
     Name                 Creation Time             State
    ------------------------------------------------------------

*  创建快照（其中快照版本信息都是记录在镜像文件中的）

# qemu-img info test7.qcow2 
    image: test7.qcow2
    file format: qcow2
    virtual size: 40G (42949672960 bytes)
    disk size: 1.8G                       // 看这个空间占用
    cluster_size: 65536
    Format specific information:
        compat: 1.1
        lazy refcounts: true
    
    # virsh snapshot-create test7         // 默认就以unix时间戳为快照名字
    Domain snapshot 1617264088 created
    
    # virsh snapshot-create-as --domain test7 snap1 --description "my first test snapshot"
    Domain snapshot snap1 created
    
    # virsh snapshot-list test7
     Name                 Creation Time             State
    ------------------------------------------------------------
     1617264088           2021-04-01 16:01:28 +0800 running
     snap1                2021-04-01 16:03:38 +0800 running
    
    # qemu-img info test7.qcow2 
    image: test7.qcow2
    file format: qcow2
    virtual size: 40G (42949672960 bytes)
    disk size: 2.7G                  // 可以看到空间增大了
    cluster_size: 65536
    Snapshot list:
    ID        TAG                 VM SIZE                DATE       VM CLOCK
    1         1617264088             390M 2021-04-01 16:01:28   00:42:39.548
    2         snap1                  390M 2021-04-01 16:03:38   00:44:47.531
    Format specific information:
        compat: 1.1
        lazy refcounts: true

*  快照配置文件

# ls /var/lib/libvirt/qemu/snapshot/test7/
    1617264088.xml  snap1.xml

**三、恢复虚拟机快照**

# virsh snapshot-revert test7 snap1

**四、删除虚拟机快照**

# virsh snapshot-delete test7

**五、快照相关其他命令**

virsh help snapshot

snapshot-create Create a snapshot from XML  
snapshot-create-as Create a snapshot from a set of args  
snapshot-current Get or set the current snapshot  
snapshot-delete Delete a domain snapshot  
snapshot-dumpxml Dump XML for a domain snapshot  
snapshot-edit edit XML for a snapshot  
snapshot-info snapshot information  
snapshot-list List snapshots for a domain  
snapshot-parent Get the name of the parent of a snapshot  
snapshot-revert Revert a domain to a snapshot

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

**往期相关内容参阅**

[KVM服务搭建及虚拟机安装][KVM]  
[KVM虚拟机扩容硬盘][KVM 1]  
[KVM虚拟机硬盘压缩][KVM 2]  
[KVM远程迁移启动报错][KVM 3]  
[KVM磁盘格式浅析][KVM 4]

[KVM]: https://blog.csdn.net/qq_25854057/article/details/109775222
[KVM 1]: https://blog.csdn.net/qq_25854057/article/details/109813314
[KVM 2]: https://blog.csdn.net/qq_25854057/article/details/109820310
[KVM 3]: https://blog.csdn.net/qq_25854057/article/details/115361708
[KVM 4]: https://blog.csdn.net/qq_25854057/article/details/115379108