design, allowing higher throughput and a greater number of devices to be
connected. You can connect up to 6 devices on this controller.
-* the *SCSI* controller, designed in 1985, is commonly found on server
-grade hardware, and can connect up to 14 storage devices. {pve} emulates by
-default a LSI 53C895A controller.
-
-* The *Virtio* controller is a generic paravirtualized controller, and is the
-recommended setting if you aim for performance. To use this controller, the OS
-need to have special drivers which may be included in your installation ISO or
-not. Linux distributions have support for the Virtio controller since 2010, and
+* the *SCSI* controller, designed in 1985, is commonly found on server grade
+hardware, and can connect up to 14 storage devices. {pve} emulates by default a
+LSI 53C895A controller. +
+A SCSI controller of type _Virtio_ is the recommended setting if you aim for
+performance and is automatically selected for newly created Linux VMs since
+{pve} 4.3. Linux distributions have support for this controller since 2012, and
FreeBSD since 2014. For Windows OSes, you need to provide an extra iso
-containing the Virtio drivers during the installation.
-// see: https://pve.proxmox.com/wiki/Paravirtualized_Block_Drivers_for_Windows#During_windows_installation.
-You can connect up to 16 devices on this controller.
+containing the drivers during the installation.
+// https://pve.proxmox.com/wiki/Paravirtualized_Block_Drivers_for_Windows#During_windows_installation.
+
+* The *Virtio* controller, also called virtio-blk to distinguish from
+the Virtio SCSI controller, is an older type of paravirtualized controller
+which has been superseded in features by the Virtio SCSI Controller.
On each controller you attach a number of emulated hard disks, which are backed
by a file or a block device residing in the configured storage. The choice of
to your VM, you can passthrough a USB device from where your SPICE client is,
directly to the VM (for example an input device or hardware dongle).
+BIOS and UEFI
+~~~~~~~~~~~~~
+
+In order to properly emulate a computer, QEMU needs to use a firmware.
+By default QEMU uses *SeaBIOS* for this, which is an open-source, x86 BIOS
+implementation. SeaBIOS is a good choice for most standard setups.
+
+There are, however, some scenarios in which a BIOS is not a good firmware
+to boot from, e.g. if you want to do VGA passthrough. footnote:[Alex Williamson has a very good blog entry about this.
+http://vfio.blogspot.co.at/2014/08/primary-graphics-assignment-without-vga.html]
+In such cases, you should rather use *OVMF*, which is an open-source UEFI implemenation. footnote:[See the OVMF Project http://www.tianocore.org/ovmf/]
+
+If you want to use OVMF, there are several things to consider:
+
+In order to save things like the *boot order*, there needs to be an EFI Disk.
+This disk will be included in backups and snapshots, and there can only be one.
+
+You can create such a disk with the following command:
+
+ qm set <vmid> -efidisk0 <storage>:1,format=<format>
+
+Where *<storage>* is the storage where you want to have the disk, and
+*<format>* is a format which the storage supports. Alternatively, you can
+create such a disk through the web interface with 'Add' -> 'EFI Disk' in the
+hardware section of a VM.
+
+When using OVMF with a virtual display (without VGA passthrough),
+you need to set the client resolution in the OVMF menu(which you can reach
+with a press of the ESC button during boot), or you have to choose
+SPICE as the display type.
+
+
Managing Virtual Machines with 'qm'
------------------------------------
projects / pve-docs.git / blobdiff