@琮儒 陈 As mentioned by @Bechir above you need to reserve ip address in order to reuse it again.
As mentioned here A virtual machine (VM) is automatically assigned a private IP address from a range that you specify, based on the subnet in which the VM is deployed. The VM retains the address until the VM is deleted. Azure dynamically assigns the next available private IP address from the subnet you create a VM in. If you want a specific IP address from the subnet assigned to the VM, assign a static IP address.
Also you can refer to below articles to restore your VM data:
https://learn.microsoft.com/en-us/azure/backup/backup-azure-arm-restore-vms
https://learn.microsoft.com/en-us/azure/backup/backup-azure-security-feature-cloud
Hope it helps!!!
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