It’s amazing how the IT industry tends to go full circle so often. Take networking as an example. We started out with the mainframe in which users sat at terminals and accessed the mainframe where all of the computing power was concentrated. Then we broke free of the rigidness of that model and went to a fully decentralized one in which users sat at smart desktop computers which accommodated the majority of their computing needs and were directed to the server only when needed. Then we went to virtual desktop infrastructure (VDI) in which users access virtual resources from a centralized location once again. A classic example of the more things change…
We are witnessing a similar situation when it comes to storage as it relates to virtualization. At the arrival of the server virtualization movement, virtual machines were simply presented with the storage that was directly attached to the host server. The internal controller of DOS is fully managed by the host server, thus the storage itself contains no intelligence. As the initial draw for server virtualization was the cost savings and green benefits of reducing the data center footprint, direct attached storage was an acceptable option. It didn’t take long however for IT managers to realize the full potential of virtualization by matching it up with shared storage. With shared storage, VMs could traverse across multiple hosts which vastly increased redundancy, scalability and up time. It also improved manageability as IT staff could perform maintenance on the physical infrastructure with no interruption to the users of the organizations.
Thus the external disk array was created. A robust hardware proprietary solution which hosted its own intelligence that allowed a trained SAN administrator to provision and manage storage. Storage was presented to the virtual machines through a backend isolated iSCSI network. The primary differentiating factor was that it shifted intelligence onto the actual storage box. This allowed the storage to be smart, allowing data centers to synchronize data redundancy amongst multiple arrays. The vendors that created these amazing devices promoted all the seemingly endless capabilities of their storage product. It was all wonderful —that is if you could afford it. Which is why so many SMB’s have been unable to take full advantage of all of these incredible solutions.
This is why we’ve come full circle with the fruition of the Virtual Server Appliance or VSA. Once again, we reverse the clock back twenty years or so to the era in which the actual storage component has no intelligence once again. But that’s actually a good thing.
COMBINING COMMODITIZED STORAGE WITH THE INTELLIGENCE AND ELASTICITY OF SOFTWARE
No matter how much money you throw at hardware, it will never be as elastic as software. Elasticity and agility have become a mainstay necessity to thrive in today’s business environment, which means that every facet of the organization must become elastic, especially IT. It is this dramatic transformation to an elastic ecosystem that is fueling the new paradigms of SDN, SDS and even the complete software defined data center. This is why both Forbes, the WSJ, and so many other publications have focused on the catch phrase, “Software is Eating the World.”
For a VSA, the storage controller runs in a VM, which manages the storage directly attached to its host. A VSA is not an appliance. It’s software, pure and simple. It then takes the DAS and creates a storage pool that is presented as network storage to all other virtual devices. Since the controller is purely software based, it can run on any type of storage component such as the classic, simple and affordable x86 platform. Whichever way you implement it, a VSA becomes a dedicated data store that can make use of all locally available unused storage for your virtual environment.
Some organizations may simply require a single VSA to provide shared storage for their VMs in a redundant disk environment. More extensive levels of high availability and redundancy can be achieved by incorporating multiple VSA’s. By clustering multiple host servers, you can eliminate any single point of failure within the data center itself. This allows SMBs to achieve first tier storage features and performance at a much more affordable price. In essence, a VSA is leveraging the intelligence elasticity of software over vulnerable hardware. If hardware vulnerability sounds devaluating to you, think again. Some of the largest enterprises in the world such as Google are running software intelligence over susceptible hardware. Even large data centers that insist on the robustness of an external intelligent disk array can utilize a VSA for data migrations between disparate storage platforms. They are also perfect for remote offices that don’t justify the cost of a traditional SAN.
With the rise of cloud computing, vendors are now offering VSA’s that can serve as a local gateway to cloud storage. Data is either stored or cached locally on the VSA residing in your data center which will then move that data onto the cloud. These storage managers regularly examine how often data is utilized and distributes it accordingly. Data that is regularly accessed on a recurrent basis is stored locally while infrequently utilized data is stored to the cloud.
There are some great VSA products available today and we want to highlight two of the leading solutions that demonstrate the clear advantages of the VSA.
VSPHERE STORAGE APPLIANCE
Although no longer supported with the exception of version 5.5 (VMware is now pushing their VSAN product), vSphere Storage Appliance vSphere offers customers a simple software storage appliance that can be bought as a single package or bundled with vSphere Essentials Plus. VMware promotes the 5 click simplicity of their product and allows you to install a VSA remotely through the hypervisor onto any ESXi host. Since it plugs straight into vSphere, VMware admins can take full advantage of features they have come to love such as Vmotion, high availability, distributed resource scheduler and fault tolerance.
HEWLETT-PACKARD LEFTHAND VIRTUAL SAN APPLIANCE
Anyone who has worked with one of HP LeftHand SAN products should feel right at home interfacing with the HP LeftHand P4000 VSA. That’s because you are working with the same software except now you are working with virtual arrays rather than hardware ones. HP simply took the software from their LeftHand SAN products and packaged it to install on an x86 server platform, turning available storage into a LeftHand storage node. The P4000 VSA is designed to work with both VMware and Microsoft HyperV and can scale out as much as necessary.
There are other VSA products out there and all work under the same philosophy – leverage the power of a software driven solution to provide all organizations the ability to manage their storage with the level of agility and elasticity required in today’s constantly changing technology and business landscapes.
