By any measure, server virtualization has been a resounding success, with pretty much all companies having virtualized at least some of their server environment and many getting close to all of it. Now these companies are taking the next step, looking to virtualize their storage and network environments as well.
To get a handle on these trends, we talked with Phil Magnuszewski, director of virtualization and cloud solutions for Carousel Industries. To understand the concepts, he says it’s helpful to start with a refresher on what server virtualization is all about.
Understanding Storage and Network Virtualization
The goal of any kind of virtualization is to build a pool of resources that are abstracted from the underlying physical environment. For servers, that means the operating system and applications are abstracted from the physical CPU, memory, I/O cards and other attributes of a physical server. “By virtualizing that environment, I build a pool of compute resources that I can carve up in any way that makes sense for my applications, taking into account performance, high availability and the ability to move things around based on the load on different applications,” Magnuszewski says.
The same concept applies to storage and network virtualization, although they deliver different benefits.
Storage Virtualization Implementation and Benefits
With storage virtualization, the idea is to pool various storage resources – everything from a high-end EMC array to a low-end HP storage system – and make them look like a single pool of storage. “I put a hypervisor in place and make all of my storage resources look like a single storage resource that I can carve up based on the demands of my data and requirements of their applications,” Magnuszewski says.
Such pooling has historically been possible only if you use a single vendor’s storage arrays. But now companies such as F5 Networks and DataCore Software are coming out with solutions that encompass multiple vendors’ storage systems. “With a hypervisor in front, I can now tier my storage based on the requirements of the application and leverage storage from multiple vendors,” he says.
The way Magnuszewski sees it, the solutions not only provide more flexibility and agility – just like server virtualization does – they can also help extend the useful life of existing storage systems. “If I bought an HP or IBM storage array years ago, chances are the drives are still good but the performance maybe isn’t what it needs to be,” he says. “But if I just want to put user data or maybe images or something like that on those systems, that’ll work fine.” Then companies could use their high-end arrays to handle applications that require high performance.
Getting to Know Network Virtualization
The network virtualization area is a bit more fuzzy, Magnuszewski says, with vendors taking varying approaches – and with good reason. “The challenge with the network is you’re still dealing with physical connections. On paper I could say I’m going to pool a set of networking resources, but I still need a switch to plug into server A and server B, and have redundant paths and such,” he says. “I haven’t seen anyone come out with a third party plug-in for networks to provide true hypervisor functionality.”
One approach is software-defined networking, which allows a network to be configured through software – an idea which Magnuszewski points out is not exactly new. But today vendors are accomplishing it via technologies such as OpenFlow, an open source API that enables multivendor switches and routers to be programmable. OpenFlow and the SDN concept was the focus of the Open Networking Summit last fall, host to some 25 demonstrations of the technology, according to Network World.
As for pure network hypervisors, though, Magnuszewski is correct that there are few options, although one vendor is getting some play, as SearchNetworking reports:
Probably the best known is the Nicira solution, which is a distributed software suite that creates scalable, fully featured, isolated virtual networks that are completely decoupled and independent from the underlying physical network. Nicira’s solution can work across any physical network and is compatible with any server hypervisor. Nicira’s open, programmable approach not only delivers Layer 2 and Layer 3 networking, it also supports Layers 4-7 services within virtual networks.
As Magnuszewski says, we’re not entirely sure how you “completely decouple” networks from the underlying physical infrastructure, so let’s color this space still in the nascent stage. Nonetheless, it bears watching.