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Redundant network connections with VMware ESX

Backup Management

Article from ADMIN 02/2010

By Timo Dreger

Virtualization doesn't necessarily provide protection against system failure if the network is a single point of failure. We explain how to set up redundant network connections for virtual machines running VMware ESX.

VMware offers numerous functions to ensure maximum failure protection and availability in a server landscape. However, this functionality mainly just takes the server hardware, and thus the CPU, RAM, and storage components, into consideration. In many cases, administrators forget that a network failure will make the virtual servers inaccessible. A switch should never be a single point of failure (Figure 1).

Figure 1: The hardware setup for redundant ESX server connections.

A sophisticated network concept is a must-have for running an ESX farm. One option is a redundant network connection using two switches, but you should not forget to include the central storage in this – whether you use iSCSI or Fibre Channel.

The physical network adapters in the ESX servers, which are connected to the switches on the network, are linked by VMware within the ESX server by means of virtual switches (vSwitch). Various connection types can run on a vSwitch, as shown in Figure 2:

Service Console Port: The service console is the management interface that supports administration via the vSphere client (or VI client in ESX3.x).
VMkernel Port: The ESX server uses a VMkernel port to access, for example, IP storage

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