Although virtualisation itself is nothing new, it's the sheer volume of work and traffic it is bringing to the network today that is making network managers sit up and take notice. The advent of virtual machines and VMotion live migration allowed IT managers to shuffle their machines around the IT landscape in order to make the most of their resources. A side effect of this is that with every virtual machine that is moved, it takes with it an array of virtual ports, virtual switches and distributed virtual switches. At some stage, the information about these moves and changes has to pass through a physical network, and that physical port will have limitations.
That is making managing virtualisation crucial. According to Paul Mew, technical director at service provider Ramsac, “It’s important to manage virtualisation throughout its lifecycle. Evaluation and test processes must be managed, as must design, implementation and development.”
So far, few are using VMotion to automate all their virtual moves and changes. But they will soon, predicts Sanjay Castelino, vice president of product marketing at SolarWinds. That is when network managers can expect the same problems that have been presenting themselves to systems and storage managers. Capacity must be planned, sprawl must be marshalled and documented, confusion must be avoided and all configurations must be tightly managed and recorded.
“Virtualisation is creating a new set of problems that the data centre boss and the network manager have never confronted before,” said Castelino. This is complicated by overlapping responsibilities in the virtual world. A problem could be the result of a glitch in the way an application addresses virtual storage, the virtual systems or the virtual network. “There could be plenty of virtual finger pointing between the various managers if you don’t get virtualisation on the network right,” said Castelino.
Using management tools can help network managers avoid and diagnose problems, and can also help to keep multiple departments working from the same sheet. “You will have four different managers with some sort of stake in this project,” said Bob Quillin, chief marketing officer at Hyper 9, a virtualization management company recently acquired by SolarWinds. “Make sure they all have the same picture of how the network is functioning and access to the same data.”
Creating a virtualisation management baseline
Before you can apply virtualisation management tools, you must start with clear goals and as clean a slate as possible. Jonathan Lampe, vice president of product management at Ipswitch File Transfer, offers the following advice to get your virtualisation project on track:
- Prepare a virtualisation overview document containing goals and objectives, success criteria, and listing constraints and high-level risks.
- Prepare a network inventory by using a Layer 2 or 3 discovery tool. This will identify physical servers in your environment and map out how everything is connected, right down to the individual port.
- Capacity planning is as important for networks as it is for systems. Measure everything -- processor utilisation, memory utilisation, storage and network usage. If a server or network is overloaded, it shouldn’t be virtualised. You may need to order more bandwidth or memory, so it is good to be forewarned.
- Understand the impact of the network on applications. Because you can lose between 10 and 50% of the network performance to virtualisation, test your most resource-intensive applications on in both "bare metal" (without virtualisation) and virtualised environments.
- Proactively plan for outages and define your service level agreements as tightly as possible. Your project will have more chance of success and achieving its target return on investment.
-- Nick Booth is an independent industry analyst. He started working in IT, networking and telecoms in the days when even the visionaries couldn’t see the Year 2000 coming.