Network bonding refers to the combination of network interfaces on one host for redundancy and/or increased throughput. Redundancy is the key factor, it is desirable to protect the entire virtualized environment from loss of service due to failure of a single physical link. This network bonding is the same as the Linux network bonding or Oracle Solaris data link aggregation. Using network bonding in Oracle VM may require some switch configuration.
While Oracle VM Manager uses the Linux terminology for network bonds, Oracle Solaris users should understand this to be equivalent to data link aggregation.
In Oracle VM, there are three modes of network bonding:
Active Backup or Active-Passive (mode=active-backup or mode=1): There is one NIC active while another NIC is asleep. If the active NIC goes down, another NIC becomes active. While this mode does not increase throughput, it provides redundancy in case of failure. Active Backup, is a safe option if you intend use VLANs.
Dynamic Link Aggregation or Link Aggregation (mode=802.3ad or mode=4): Aggregated NICs act as one NIC which results in a higher throughput, but also provides failover in the case that a NIC fails. Dynamic Link Aggregation requires a switch that supports IEEE 802.3ad. Dynamic Link Aggregation is the preferred mode of network bonding, but requires that the network is configured correctly on the switch.
Adaptive Load Balancing or Load Balanced (mode=balance-alb or mode=6): The network traffic is equally balanced over the NICs of the machine to provide higher throughput and failover is also supported to provide redundancy. Unlike Dynamic Link Aggregation, Adaptive Load Balancing does not require any particular switch configuration.
NoteAdaptive Load Balancing or Load Balanced (mode=balance-alb or mode=6) bonding:
Is not currently supported for SPARC servers.
Is supported in x86 environments only.
Might not work correctly with VLAN traffic. It is not supported to have virtual machine networks on VLANs with Load Balanced bond ports.
During installation of Oracle VM Server, the network interface (selected when prompted for the management port) is configured as a bonded interface. The bond is created with only one interface. This is done because the reconfiguration of the management interface on the Oracle VM Servers is not supported. You can add a second interface to the already existing bond device without affecting the configuration of the original interface. This is illustrated in Figure 5.2, “Network bonding”, where a second network interface is added to bond0, the network bond created during installation. By default, the bond mode is set to Active Backup for the management network.
Figure 5.2, “Network bonding” also illustrates the configuration of a second bonded interface, bond1, which can be used for other network usage, such as the virtual machine channel. Separation of network functions into different channels is discussed in more detail in Section 5.6, “How are Network Functions Separated in Oracle VM?”.
Note that once a network port becomes part of a bond, it becomes a slave port. In this configuration, Oracle VM Manager is not able to actually change any configuration parameters for the slave port. All configuration changes are applied to the bond interface. The only action that Oracle VM Manager can apply to a slave port is to remove it from the bond. Values for some parameters, such as MTU, on the slave port may reflect the value of the bond interface within Oracle VM Manager or when using any networking tools directly on the command line of an Oracle VM Server although only the values reflected for the bond are actually ever used. The original configuration file for the slave port is never updated as long as it is part of the bond. This means that when a port is removed from a bond, it reverts to its original configuration and any configuration changes to parameters that applied to the bond are not applied to the released port.
It is important to understand that the actual cabling of Ethernet interfaces is important when using network bonds. If you are using Active Backup (mode=active-backup or mode=1) or Load Balanced (mode=balance-alb or mode=6), the Ethernet ports can be connected to alternate switches as shown in Figure 5.3, “Network bonding for modes 1 and 6”. If you are using Dynamic Link Aggregation (mode=802.3ad or mode=4), the Ethernet ports can also be connected to alternate switches, but only if the switches support Virtual Switching System (VSS) or Virtual Path Channel (vPC). This is illustrated in Figure 5.4, “Network bonding for mode 4 with switch support for VSS or vPC”. If VSS or vPC is not supported for the switch you are using, the Ethernet ports must be cabled to the same switch, which is configured for dynamic link aggregation (IEEE 802.3ad). This is illustrated in Figure 5.5, “Network bonding for mode 4 with no switch support for VSS or vPC”.
If you are using Dynamic Link Aggregation (mode=802.3ad or mode=4), refer to the switch product documentation or available support channels to determine whether support for VSS or vPC is available for the switch you are using.
For more information on configuring bonds in Oracle VM, see Bond Ports Perspective in the Oracle VM Manager User's Guide.