VIO Shared Ethernet Setup

This article discusses the steps involved in setting up VIO Shared Ethernet. First of all, why do we need it? Why can't we assign a physical Ethernet adapter to Logical Partition (LPAR) and configure it?
Imagine a physical server (Managed Power system) having just four Ethernet adapters. Now, if we assign one physical adapter per LPAR, we will run out of Ethernet adapter as soon as we build four LPARS. If there is a requirement to build 10 LPARs, how do we suffice the Ethernet adapter requirement? This is where the VIO server comes handy to share the physical adapters across all the LPARs.
TheVIO shared Ethernet adapter will help in sharing a physical adapter across all the LPARs. If we are going to use one physical adapter for all the 10 LPARs, Can it sustain the load i.e. all the network traffic coming from all the 10 LPARs? In the VIO, we can create link aggregation using multiple physical adapters to address the network traffic needs of the LPARs. Now we will talk about how to setup the link aggregation and shared Ethernet in the VIO servers.

Let’s say we have the following physical Ethernet adapters for public network:

Physical Ethernet Adapters
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ent0 - Public network

ent1 - Public network

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Create two Virtual Ethernet Adapters in VIO LPAR Profile. One will be used for communication between VIO and LPARs and another one for control channel. Control channel is used in the dual-VIO setup and used for heartbeat mechanism to detect failures.

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ent2 - Virtual for Public - VLAN ID 1

ent3 - Virtual Control channel for public - VLAN ID 99
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Command to Configure link aggregation

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mkvdev -lnagg ent0,ent1 -attr mode=8023ad
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The above command will create ent4 which is an aggregated link of two physical adapter ent0 and ent1. The mode 8023ad specifies to use IEEE 802.3ad standard and Link Aggregation Control Protocol (LACP) at the switch side. Have the network team configure the etherchannel on the switch ports.

Now it’s time to create the shared Ethernet adapter.
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mkvdev -sea ent4 -vadapter ent2 -default ent2 -defaultid 1 -attr ha_mode=auto ctl_chan=ent3
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The above command will create ent5 where you can assign IP address of the VIO servers for connectivity. Now in the client LPAR profiles, create virtual Ethernet with VLAN ID as 1 to make use of shared Ethernet adapter.


Important Note: In the Dual-VIO setup, make sure control channel is configured properly with proper VLAN ID on both the VIO servers. Any mis-configuration will flood the network with BPDU packets.