Configuring Jumbo Frames - UG1739

X4 series adapters support jumbo frames on the Enterprise datapath, with a frame size (MTU) from 1500 bytes to 9100 bytes.

X4 series adapters do not support jumbo frames on the Express datapath, and the frame size (MTU) must be 1500 bytes.

The default frame size is 1500 bytes.

You can enable jumbo frames for an interface only if it always uses the Enterprise datapath. If an interface is passing traffic for accelerated applications it might use the Express datapath, and so you should not change the MTU from its default of 1500 bytes.

You can identify and reconfigure frame sizes using the ip command:

• To identify the current frame size:

  ip link show dev <interface>

• To set the new frame size to value N:

  ip link set dev <interface> mtu N

  The frame size must be a value between 1500 and 9100.

To make the changes permanent, edit the network configuration file for the <interface> (/etc/sysconfig/network-scripts/ifcfg-<interface>). Append an MTU configuration directive, which specifies the size of the frame in bytes. For example:

MTU=9100