A Volume is a virtual hard disk located on distributed network storage.
When creating Volume-backed Virtual Machines, a Volume is created automatically and used as the boot disk. A Volume containing a configured operating system and user data can be reused to create a new Virtual Machine. For more details, see: How to avoid paying for a Virtual Machine that is currently not in use.
Important: If you do not plan to use the automatically created Volume in the future, you must delete it manually after removing the Virtual Machine.
You can also create Volumes of any size and attach them to Virtual Machines as additional disks.