E.5. Configuring Jumbo Frames
The Maximum Transmission Unit (MTU) setting determines the maximum amount of data transmitted with a single Ethernet frame. Using a larger value results in less overhead since each frame adds data in the form of a header. The default value is 1500 and using a higher value requires the configuration of the switch port to support jumbo frames. Most switches support an MTU of at least 9000, but many are configured for 1500 by default.
The MTU of a VLAN cannot exceed the MTU of the physical interface. Make sure to include the MTU value on the bond and/or interface.
The Storage, Storage Management, Internal API, and Tenant networking all benefit from jumbo frames. In testing, Tenant networking throughput was over 300% greater when using jumbo frames in conjunction with VXLAN tunnels.
Note
It is recommended that the Provisioning interface, External interface, and any floating IP interfaces be left at the default MTU of 1500. Connectivity problems are likely to occur otherwise. This is because routers typically cannot forward jumbo frames across Layer 3 boundaries.
- type: ovs_bond name: bond1 mtu: 9000 ovs_options: {get_param: BondInterfaceOvsOptions} members: - type: interface name: nic3 mtu: 9000 primary: true - type: interface name: nic4 mtu: 9000 # The external interface should stay at default - type: vlan device: bond1 vlan_id: {get_param: ExternalNetworkVlanID} addresses: - ip_netmask: {get_param: ExternalIpSubnet} routes: - ip_netmask: 0.0.0.0/0 next_hop: {get_param: ExternalInterfaceDefaultRoute} # MTU 9000 for Internal API, Storage, and Storage Management - type: vlan device: bond1 mtu: 9000 vlan_id: {get_param: InternalApiNetworkVlanID} addresses: - ip_netmask: {get_param: InternalApiIpSubnet}