You've prepared your critical applications for virtualization. You've tested and selected a virtualization platform. You've built out a fleet of virtual servers and migrated your applications to them. Your hypervisor is configured and you're ready to start sending your uses to your spiffy new virtual environment. Wait. There's one more step you may want to take.
Just because your servers are virtual doesn't mean they don't need network infrastructure. Running multiple virtual servers on the same machine can create I/O bottlenecks and reduce the efficiency of your applications. Fortunately, you can use virtual I/O technology to make sure you're getting the most out of your network infrastructure and eliminate bottlenecks.
A typical hypervisor environment will require six to eight physical network cards. Each of those cards will need a network cable, and each cable will need a port on a switch. Your virtual servers are getting physical fast.
I/O virtualization provides virtual network cards that satisfy these requirements without requiring actual physical cards. The hypervisors can't tell the difference. These virtual cards can share a single cable using a single port on a switch, cutting down on the gear required to support your servers.
You can use I/O virtualization to:
- Reduce costs, thanks to having less hardware to purchase.
- Reduce complexity, thanks to having fewer cables and a central, virtual place to manage connections.
- Reduce space requirements, again thanks to having less hardware and fewer cables.
Some I/O virtualization solutions also offer bandwidth throttling. In a physical networking environment you're typically faced with a choice of using either a one GB connection or a 10 GB connection. If you have a server that requires three GB of bandwidth you'd need to provide a 10 GB connection. The other seven GB of capacity are wasted. Worse, if a server that typically doesn't need more than a one GB connection suddenly needs two, you need to upgrade the whole connection.
Using virtualization, you can allocate capacity to servers however you see fit. If you have three servers requiring three GB each, you can split one 10 GB connection instead of proving three separate 10 GB connections. If one of those servers ends up needing more bandwidth, you can dynamically allocate bandwidth from another server.
Several vendors offer I/O virtualization solutions, including established companies like Brocade, Cisco, Dell, HP and IBM as well as younger companies like 3Leaf and Xsigo. Considering the benefits of virtualizing your networks, it's worth looking into early in your migration plans.
Photo by Simon Cockell