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}
