How to configure jumbo frames on Scaleway Dedibox RPN

The RPN network supports by default jumbo frames. This allows you to configure your network interfaces with an MTU 9000 (Maximum transfer unit).

This technology allows you to significantly minimize the interruptions and processor latencies needed for data transfer. The performance gain can reach up to +20% on resource-intensive applications such as iSCSI, NFS, and DRDB.

How to check your current MTU settings

1. To check your current MTU settings, type:

   ifconfig ethX | grep MTU
   

   Tip

   Replace ethX with the name of your RPN interface.

2. An output like the following example displays:

   root@my-dedibox-server:~# ifconfig ethX | grep MTU
         UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
   

   In the example above you can see the current MTU of the network interface is set to the Ethernet standard of 1500.

How to set the MTU 9000

On Linux

CentOS

1. Open the file /etc/sysconfig/network-scripts/ifcfg-ethX, where X is the number of your interface, in a text editor. Then add the following line to it:

   MTU="9000"
   

2. Restart the network service:

   service network restart
   

Debian

1. Open the file /etc/network/interfaces in a text editor and insert mtu 9000 below the line iface ethX inet static:

   auto ethX
   iface ethX inet static
   mtu 9000
   [...]
   

2. Restart the network service:

   service network restart
   

Ubuntu

1. Open the Netplan configuration file /etc/netplan/01-netcfg.yaml in a text editor and add the line mtu: 9000 in the configuration of the RPN interface:

   ethernets:
       enp3s0:
           dhcp4: true
       enp4s0:
           addresses:
               - 192.168.0.10/24
           gateway4: 192.168.0.1
           mtu: 9000
           nameservers:
               addresses:
                   - 1.1.1.1
                   - 2.2.2.2
   

2. Save the file, exit the text editor, and reload the network configuration:

   sudo netplan apply
   

On Windows

To change the MTU settings on Windows, you can use a tool like TCP Optimizer to modify the MTU settings.

1. Download and start the tool.
2. In the bottom right corner, click Custom.
3. Go to Network adapter selection and select the RPN interface.
4. Set the MTU value to 9000.
5. Click on Apply change to update the MTU settings.