Openfiler is an rPath Linux-based, free and open source NAS/SAN software solution. We have previously written a comparative review of Openfiler and FreeNAS, the other free and open source NAS/SAN software solution. One of the networking features of Openfiler is interface bonding. In this tutorial, we provide some guidance on how to configure interface bonding in Openfiler 2.3, the latest stable version.
Interface bonding is a means of aggregating two or more network interface cards (NICs) for the purpose of setting up load balancing, fault tolerance, and creating high availability systems. Openfiler supports the following bonding modes:
- Active backup
- Balance – XOR
- 802.3ad (IEEE 802.3ad Dynamic link aggregation)
- Balance-tlb (Adaptive transmit load balancing)
- Balance-alb (Adaptive load balancing)
The simplest and most basic form of interface bonding is accomplished using the Active Backup mode, which allows for the aggregation (bonding) of two or more interfaces, such that if (for whatever reason) one interface becomes inactive, the system will still be accessible through the other “standby” interface. Both interfaces could be connected to the same switch, or to different switches. The latter case makes it possible to access a system via another network segment if the primary route to the system fails while the former implements a “NIC failover”, for those rare occasions when a NIC “dies”. To configure interface bonding using Active Backup mode in Openfiler 2.3 is pretty simple.
This is a step-by-step guide, with screenshots.
Note: In this example, we are using a PC with two NICs connected to the same network segment. In a real world case, you are most likely going to do this using a PC with two NICs connected to separate networks segments
The first step, of course, is to have an Openfiler installation, which should take you no more than 15 minutes. You may download the latest stable version, Openfiler 2.3, if you have not already done so.
Administering Openfiler is via a browser-based interface. To access the admin interface, use the following default access information:
- username: openfiler
- password: password
Here we have the network setting of the system, with the network interfaces available on the system. Bonding requires at least two network interfaces, and in our test system, we have two (interfaces) – eth0 and eth1 – configured and ready to use. Click on “Create Bonded interface” link at the bottom of the list of configured interfaces to start creating the bonded interface.
From this window, you’ll have to select the interfaces that you want to use in creating the bonded interface. Once selected and after the bonding has been finalized, the interfaces become “slaves’ of the bonded interface – bond0.
What we need to do here is specify the settings of the bonded interface – bond0 – that we are about to create. The bonded interface is a virtual network interface that must have a unique IP address. This IP address becomes the new IP address of the system, and this is the IP addresss that will be used to access the system once bonding is configured. For this example, we are assigning bond0 an IP address of 192.168.1.15, with a netmask of 255.255.255.0.
The next setting we need to choose is the bonding mode. Since for this tutorial we are try to create a redundant interface, we select the first option – Active Backup.
Sticking with the default values for the other bonding options will do it for this example. Click “Continue” when you are done. Be aware that after you click “Continue”, you most likely will have to reboot the machine and access the admin interface using the newly created virtual IP address of bond0.
After rebooting, you should see a new interface – bond0 – when you access the admin interface, or when you type ifconfig from the console. At this point, if one of the real interfaces (in this case, eth0 or eth1) goes down, the system will still be accessible. If you are doing this for the first time, give it a try by un-plugging one of the Ethernet cables. Note that while the virtual interface, bond0, has a unique IP address, it does not have a MAC address, but assumes the MAC address of the primary interface.
Setting up bonding using the active backup mode is the simplest example of how to get used to creating a bonded interface in Openfiler 2.3. You may find out more about the other bonding modes and bonding settings here.