Azure virtual machines use disks to store the VMs operating system, applications and data. When an Azure virtual machine is created, two disks are automatically attached to the virtual machine. The Operating system disk and Temporary disk. The default OS drive letter is C: and size is 127 GB. When an Azure virtual machine OS disk is out of space, you should extend the OS disk. You can extend the OS disk by using Azure portal. Here, you are using Azure portal to extend the Azure virtual OS disk.
