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Diffstat (limited to 'docs/system/virtio-net-failover.rst')
| -rw-r--r-- | docs/system/virtio-net-failover.rst | 51 |
1 files changed, 28 insertions, 23 deletions
diff --git a/docs/system/virtio-net-failover.rst b/docs/system/virtio-net-failover.rst index 6002dc5..0cc4654 100644 --- a/docs/system/virtio-net-failover.rst +++ b/docs/system/virtio-net-failover.rst @@ -26,43 +26,48 @@ and standby devices are not plugged into the same PCIe slot. Usecase ------- - Virtio-net standby allows easy migration while using a passed-through fast - networking device by falling back to a virtio-net device for the duration of - the migration. It is like a simple version of a bond, the difference is that it - requires no configuration in the guest. When a guest is live-migrated to - another host QEMU will unplug the primary device via the PCIe based hotplug - handler and traffic will go through the virtio-net device. On the target - system the primary device will be automatically plugged back and the - net_failover module registers it again as the primary device. +Virtio-net standby allows easy migration while using a passed-through +fast networking device by falling back to a virtio-net device for the +duration of the migration. It is like a simple version of a bond, the +difference is that it requires no configuration in the guest. When a +guest is live-migrated to another host QEMU will unplug the primary +device via the PCIe based hotplug handler and traffic will go through +the virtio-net device. On the target system the primary device will be +automatically plugged back and the net_failover module registers it +again as the primary device. Usage ----- - The primary device can be hotplugged or be part of the startup configuration +The primary device can be hotplugged or be part of the startup configuration - -device virtio-net-pci,netdev=hostnet1,id=net1,mac=52:54:00:6f:55:cc, \ - bus=root2,failover=on +.. code-block:: shell - With the parameter failover=on the VIRTIO_NET_F_STANDBY feature will be enabled. + -device virtio-net-pci,netdev=hostnet1,id=net1,mac=52:54:00:6f:55:cc,bus=root2,failover=on + +With the parameter ``failover=on`` the VIRTIO_NET_F_STANDBY feature will be enabled. + +.. code-block:: shell -device vfio-pci,host=5e:00.2,id=hostdev0,bus=root1,failover_pair_id=net1 - failover_pair_id references the id of the virtio-net standby device. This - is only for pairing the devices within QEMU. The guest kernel module - net_failover will match devices with identical MAC addresses. +``failover_pair_id`` references the id of the virtio-net standby device. +This is only for pairing the devices within QEMU. The guest kernel +module net_failover will match devices with identical MAC addresses. Hotplug ------- - Both primary and standby device can be hotplugged via the QEMU monitor. Note - that if the virtio-net device is plugged first a warning will be issued that it - couldn't find the primary device. +Both primary and standby device can be hotplugged via the QEMU +monitor. Note that if the virtio-net device is plugged first a warning +will be issued that it couldn't find the primary device. Migration --------- - A new migration state wait-unplug was added for this feature. If failover primary - devices are present in the configuration, migration will go into this state. - It will wait until the device unplug is completed in the guest and then move into - active state. On the target system the primary devices will be automatically hotplugged - when the feature bit was negotiated for the virtio-net standby device. +A new migration state wait-unplug was added for this feature. If +failover primary devices are present in the configuration, migration +will go into this state. It will wait until the device unplug is +completed in the guest and then move into active state. On the target +system the primary devices will be automatically hotplugged when the +feature bit was negotiated for the virtio-net standby device. |