Updated at: 2022-12-09 03:49:50
To back up VM configuration version 8.0/9.0,
Step 1 The 
client on the Hyper-V node where the target VMs reside invokes the WMI interface to create a VM RCT snapshot (checkpoint).
Step 2 The client obtains the disk path and RCT information of the VM snapshot (checkpoint), and mounts the virtual disks corresponding to the VMs to the Hyper-V node.
Step 3 Query changed data block information based on the last backup RCT information, u
sed to calculate the data blocks to be backed up for incremental backup. For full backup, this step is skipped.
Step 4 
The client reads the data in the virtual disks mounted to the Hyper-V node, and backs up the RCT information of the virtual disk and the VM configuration file vm.xml or vvm.vmcx, vm.vmrs.
Step 5 Delete the snapshot (checkpoint) after the backup is completed.