virsh 保护命令 virtual protect rebase

virsh list --all 

查看虚拟机列表

virsh list

virsh domblklist centos6.5

qemu-img snapshot -l /var/lib/libvirt/images/centos6.5.qcow2

备份：

virsh qemu-monitor-command DOMAIN --pretty '{ "execute": "transaction", "arguments": { "actions": [ { "type": "block-dirty-bitmap-add", "data": {"node":"drive-virtio-disk0", "name":"bitmap0"}}, { "type": "drive-backup", "data": {"device": "drive-virtio-disk0", "target": "/opt/backup/top.img","sync":"top" }} ]} }'

# ...运行一段时间... virsh qemu-monitor-command DOMAIN --pretty '{ "execute" : "drive-backup" , "arguments" : { "device" : "drive-virtio-disk0" , "sync" : "incremental" , "bitmap" : "bitmap0" , "target" : "/opt/backup/inc.0.qcow2" } }'

# ...又运行一段时间... virsh qemu-monitor-command DOMAIN --pretty '{ "execute" : "drive-backup" , "arguments" : { "device" : "drive-virtio-disk0" , "sync" : "incremental" , "bitmap" : "bitmap0" , "target" : "/opt/backup/inc.1.qcow2" } }'

如果之前已经创建过bitmap，此刻想忽略bitmap，重新做一次完整备份，并重置bitmap（用于接下来的增量备份），则可以

{ "execute": "transaction", "arguments": { "actions": [ {"type": "block-dirty-bitmap-clear", "data": {"node": "drive-virtio-disk0", "name": "bitmap0"} }, {"type": "drive-backup", "data": {"device": "drive-virtio-disk0", "target": "/path/to/new_full_backup.img", "sync": "top"} } ] } }

# 查询虚拟机的所有磁盘的bitmap

virsh qemu-monitor-command DOMAIN --pretty '{ "execute": "query-block" }'

查看备份任务

# 通过qmp查看

virsh qemu-monitor-command DOMAIN --pretty '{ "execute": "query-block-jobs" }'

全量：

virsh qemu-monitor-command DOMAIN '{ "execute" : "drive-backup" , "arguments" : { "device" : "drive-virtio-disk0" , "sync" : "top" , "target" : "/opt/backup/top.img" } }'

解决qemu-img commit   的差异

1.xp xp_snap1 xp_snap2 xp_snap3 xp_new

镜像xp_new与xp的关系如上，左依次为右的backing file

如要删除xp_snap2时，(即关系变为xp xp_snap1 xp_snap3 xp_new)

先用qemu-img commit xp_snap2 命令将xp_snap2的内容commit到xp_snap1

再将xp_snap3的backing file指向xp_snap1

qemu-img rebase -f qcow2 -b xp_snap1 -F qcow2 xp_snap3 (将会比较xp_snap1与xp_snap2是否一致)

qemu-img commit xp_snap3

永久bitmap 

virsh qemu-monitor-command DOMAIN --pretty '{ "execute": "transaction", "arguments": { "actions": [ { "type": "block-dirty-bitmap-add", "data": {"node":"drive-virtio-disk0", "name":"bitmap0","persistent": true}}, { "type": "drive-backup", "data": {"device": "drive-virtio-disk0", "target": "/opt/backup/top.img","sync":"top" }} ]} }'

 删除bitmaps

virsh qemu-monitor-command DOMAIN --pretty '{ "execute": "block-dirty-bitmap-remove","arguments":{"node":"drive-virtio-disk0","name":"bitmap0"} }'

 清空bitmaps

virsh qemu-monitor-command DOMAIN --pretty '{ "execute": "block-dirty-bitmap-clear","arguments":{"node":"drive-virtio-disk0","name":"bitmap0"} }'

增加bitmaps

virsh qemu-monitor-command DOMAIN --pretty '{ "execute": "block-dirty-bitmap-add","arguments":{"node":"drive-virtio-disk0","name":"bitmap0"} }'

永久增加bitmaps

virsh qemu-monitor-command DOMAIN --pretty '{ "execute": "block-dirty-bitmap-add","arguments":{"node":"drive-virtio-disk0","name":"bitmap0","":true} }'

问题：

https://www.mail-archive.com/qemu-devel@nongnu.org/msg592973.html

 1

{"id":"libvirt-42","error":{"class":"GenericError","desc":"Can't make
bitmap 'bitmap0' persistent in 'drive-virtio-disk1': Bitmap with the
same name is already stored"}}

In other word, when qemu crash, the qcow2 image remain the incomplete
persistent bitmap.

persistent bitmap will be inconsistent when qemu  crash,

crash will genrerate this question。

问题2：

Cannot store dirty bitmaps in qcow2 v2 files



参考：
https://www.lizi.tw/soft/16760.html      QEMU/KVM磁盘的在线完整及增量备份

mount -t nfs 192.168.10.161:/mnt/vg /home/kvm -o rw

 一键接管：

virsh domblklist demo

virsh dumpxml demo > demo.xml

qemu-img rebase -u

qemu-img commit inc2.qcow2

 qemu-img rebase -u -b base.img commit.img

qemu-img commit  commit.img

外置快照的删除(qemu-img commit/rebase)

1.方法

我们需要删除快照sn2 当前: [centosbase] <– centos2 <– centos2_sn1 <– centos2_sn2 <– centos2_sn3 <– centos2_sn4(当前使用磁盘) 目标: [centosbase] <– centos2 <– centos2_sn1 <—————— centos2_sn3 <– centos2_sn4(当前使用磁盘) 现在删除第二个快照(sn2).有两种方式: (1): 复制sn2数据到后端sn1,将会commit所有sn2中的数据到sn2的backing file(sn1),和virsh blockcommit类似 (2): 复制sn2数据到前段sn3,将会commit所有sn2中的数据到sn2的overlays,和virsh blockpull类似 注意: 必须保证sn1没有被其他快照作为后端(即centos2_sn1只被当前链使用)

2.(1): 复制sn2数据到后端sn1

qemu-img commit centos2_sn2.qcow2
qemu-img rebase -u -b centos2_sn1.qcow2 centos2_sn3.qcow2     #让sn3指向sn1

#现在sn1中包含了之前的sn1/sn2中的数据,所以此时不再需要sn2中的数据,直接让sn3指向sn1即可,可以直接删除sn2 注意: -u代表’Unsafe mode’ – 此模式下仅仅修改了指向到的backing file名字(不复制数据)

修改网卡 

修改img  路径

virsh define  /mnt/102.xml

virsh start name_102

qemu-img -V

查看

qemu-img version 4.1.0

qemu >=2.10  才能  永久bitmaps 

qemu >= 2.10

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原文链接：https://www.cnblogs.com/rebrobot/p/15533530.html
参考：

https://opengers.github.io/virtualization/kvm-libvirt-qemu-5/
https://qemu-project.gitlab.io/qemu/interop/dbus-vmstate.html
https://qemu-project.gitlab.io/qemu/system/index.html