// http://pve.proxmox.com/wiki/KVM
// http://pve.proxmox.com/wiki/Qemu_Server
-Qemu (short form for Quick Emulator) is an opensource hypervisor that emulates a
+Qemu (short form for Quick Emulator) is an open source hypervisor that emulates a
physical computer. From the perspective of the host system where Qemu is
running, Qemu is a user program which has access to a number of local resources
like partitions, files, network cards which are then passed to an
Qemu inside {pve} runs as a root process, since this is required to access block
and PCI devices.
+
Emulated devices and paravirtualized devices
--------------------------------------------
measured with `iperf(1)`. footnote:[See this benchmark on the KVM wiki
http://www.linux-kvm.org/page/Using_VirtIO_NIC]
+
Virtual Machines settings
-------------------------
Generally speaking {pve} tries to choose sane defaults for virtual machines
(VM). Make sure you understand the meaning of the settings you change, as it
could incur a performance slowdown, or putting your data at risk.
+
General Settings
~~~~~~~~~~~~~~~~
General settings of a VM include
* *Name*: a free form text string you can use to describe the VM
* *Resource Pool*: a logical group of VMs
+
OS Settings
~~~~~~~~~~~
When creating a VM, setting the proper Operating System(OS) allows {pve} to
clock to use the local time, while Unix based OS expect the BIOS clock to have
the UTC time.
+
Hard Disk
~~~~~~~~~
Qemu can emulate a number of storage controllers:
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).
-Managing Virtual Machines with 'qm'
+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`
------------------------------------
qm is the tool to manage Qemu/Kvm virtual machines on {pve}. You can
PARAMETER: value
Configuration files are stored inside the Proxmox cluster file
-system, and can be accessed at '/etc/pve/qemu-server/<VMID>.conf'.
+system, and can be accessed at `/etc/pve/qemu-server/<VMID>.conf`.
Options
~~~~~~~
Locks
-----
-Online migrations and backups ('vzdump') set a lock to prevent incompatible
+Online migrations and backups (`vzdump`) set a lock to prevent incompatible
concurrent actions on the affected VMs. Sometimes you need to remove such a
lock manually (e.g., after a power failure).
projects / pve-docs.git / blobdiff