The Hidden Costs Of Virtualization Part 2: Networking

Saturday, 30 September 2006 by Michel Roth

The second part of the article on the "hidden costs" of virtualization by David Marshall and Dan Knezevic has been published: Part one of this discussion on hidden virtualization costs went over the power and heat costs and the management concerns of virtualization. Now, in part two, we will turn our attention to networking issues and the problem of virtual machine sprawl. Part three will discuss licensing, performance and storage.

Virtualized servers have unique networking concerns. In a virtual network, you will see a larger than average number of IP addresses, more than usual subnets and VLANs, high packets per second, greater susceptibility to switch port problems, greater need to plan machine per host density and MAC address management issues.

From the networking perspective, it is important to think of virtual machines as being no different than physical servers. It is extremely important to plan out the configuration of the network and its subnetting based on the total number of virtual machines and physical servers. Otherwise, you are going to be in for a rude awakening.

Read the entire article here.