SAN storage is a common IP SAN storage device that provides LUNs externally. The cloud platform creates volumes on the LUNs provided by the cloud platform and mounts the volumes to VMs.
Advanced SAN is a Huawei storage device, also called a small LUN. If you want to create a 10 GB disk for a VM, create a 10 GB LUN on the storage device, attach the VM to the VM as the disk of the VM. That is, the LUN provided by the cloud platform is a VM disk.