A virtual disk image is a file or group of files in which a virtual machine stores its data. In Proxmox, a VM configuration file can be recreated and used to attach a disk image. But if the image itself is lost, it can only be restored from a backup. There are different types of virtual disk image formats available to be used with a virtual machine. It is essential to know the different types of image formats in order to have an optimally performing VM. Knowing the disk images also helps prevent the premature shortage of space, which may occur by over-provisioning virtual disks.
Proxmox supports the .raw, .qcow2, and .vmdk virtual disk formats. Each format has its own set of strengths and weaknesses. The image format is usually chosen based on the function of the virtual machine, storage system in use, performance requirement, and available budget. The following screenshot shows the menu where we can choose an image type during virtual disk creation...
