[SOLVED] Question about exact KVM backup & snapshot mechanism

[curious_1]

Hello, I was wondering how does exactly KVM backup and snapshoting works in Proxmox VE for qcow2 based VMs. I've been looking for an answer on the web but found nothing. If it's not a company secret I'd like to ask what kind of tools and commands are used to perform backup and snapshot tasks. Is KVM live (snapshot) backup something like:

qemu-img snapshot -c "backup_point" /var/lib/.../vm.img   qemu-img convert -f qcow2 -O qcow2 -s "backup_point" /var/lib/.../vm.img /var/lib/.../backup/vm_bak.img   lzop /var/lib/.../backup/vm_bak.img   qemu-img snapshot -d "backup_point" /var/lib/.../vm.img

? And how does snapshots for KVM works? As far as I can see it's a full snapshot containing VM memory state and such, so QEMU Monitor "savevm" command maybe? But as far as I know that command doesn't create a new disk image file which I can see is created by issuing snapshot command from Proxmox web panel. I'd be very grateful for satisfying my curiosity. Best regards, curious_1

 

[dietmar]

snapshots basically use savevm and storage internal snapshots for disk.

backup uses kvm backup code, for details see:

http://git.qemu.org/?p=qemu.git;a=b...654d5214121abc6e621a2c25fcbfb441b5c47;hb=HEAD

 

[curious_1]

Thank you very much for your answer dietmar, that is exactly what I wanted to know. Best regards, curious_1

 

[fireon]

Thank you very much for your answer dietmar, that is exactly what I wanted to know. Best regards, curious_1

When it is solved for you, please set the thread to [solved]

Thanks!