Configuring MTU on public interfaces
The MTU property controls the maximum transmission unit size for an Ethernet frame. The standard maximum transmission unit size for Ethernet is 1500 bytes (without headers). MTU defines the largest data packet that a network-connected device accepts. The network routers check the size of each IP packet that they receive against the MTU of the next router that will receive the packet. If the packet exceeds the MTU of the next router, the first router breaks the payload into two or more packets, each with its own headers.
You can manage the MTU values using both the GUI and RESTful APIs. In a NetBackup Flex Scale appliance, the range of MTU is between 1500 to 9000.The MTU value changes the payload size of the packets which modifies the data transfer rate. If the MTU value is edited, the changes are reflected across the cluster.
To edit the value that has been set for MTU using the NetBackup Flex Scale GUI:
Navigate to or .
Go to the network that you want to modify. Either click on the kebab menu and choose or click button from the subsection of the chosen interface.
In the pop-up, enter the new value and click .
Notification events are raised when the MTU values are modified.
Note:
When you use the GUI to set the MTU value on management NICs, capacity validation of the NIC is not performed because there is no guarantee that all the nodes will have the same direct public switch connections to their management interfaces on a public network. Hence, ensure the MTU value you want to set is actually supported at NIC and switch level on all the nodes. Else, SSH commands between the nodes may start failing intermittently or operations such as add node may hang.
The following RESTful APIs are available to configure and manage MTU values:
GET /api/appliance/v1.0/network/mtu: Fetches the MTU values for all interfaces.
GET /api/appliance/v1.0/network/mtu/{interfaceName}: Fetches the MTU value for the specified interface.
PATCH /api/appliance/v1.0/network/mtu/{interfaceName}: Modifies the MTU value for the specified interface and sets it to the value mentioned in the payload of the API.