Virtual device types emulate the bus or device nature of physical drives. Proxmox allows quite a few additional virtual drives to be added to a VM. The following table shows the bus types supported in Proxmox and the maximum number of allowed disk devices per VM by Proxmox:

Out of four supported bus types, the VirtIO bus type gives the maximum performance in almost all situations. VirtIO disk images are recognized by Linux without any additional work during OS installation. However, when installing Windows in a VM, VirtIO drives are not recognized. Additional VirtIO drives need to be added at the time of Windows installation. We will look into best practices for using the VirtIO bus type with Windows OSes later in this chapter.