Virsto Software tackles storage virtualization for Hyper-V

Q&A: Virsto One provides high-performance, thin-provisioned snapshots and clones, and dramatically increases I/O performance for Hyper-V environments

Startup Virsto (named for "virtual storage") Software burst on the virtualization scene with new software designed to dramatically improve the storage performance for Microsoft Hyper-V virtual environments. The company's new Virsto One software tackles common problems found with enterprise data storage management in a server virtualization environment.

The new software aims to reduce storage sprawl, simplify storage management, increase storage performance, and eliminate excessive storage costs -- a major undertaking.

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Virsto One is delivered as a simple plug-in and installs into the parent partition of the Microsoft Hyper-V hypervisor. From an architecture view, it consists of a filter driver and a system service that talks directly to standard windows management interface (WMI). Because it is accessible by any compatible WMI service, it offers users a seamless interface with PowerShell integration and Microsoft Management Console (MMC).

The filter driver resides above the raw volume layer and presents a virtual disk as a virtual hard drive (VHD) object to the parent partition. Hyper-V manager then attaches these VHD objects to guest virtual machines. According to the company, Virsto One VHDs are high-performing, thin-provisioned dynamic storage objects that conform to Microsoft-fixed VHD specifications; therefore, they are automatically compatible with all Microsoft system storage functionality.

To find out more, I spoke with Mark Davis, the CEO of Virsto Software.

InfoWorld: What are some of the core issues that your company has found when looking at virtualization and storage?

Davis: Almost all storage technologies used today are based on techniques designed for physical servers. Unfortunately, virtual servers invalidate key assumptions built into such products. Because of this, storage for virtual environments is far from optimal.

Users of virtual servers have four complaints. First, virtual servers consume up to 30 percent more disk space than physical servers, caused by the well-known "VM sprawl" problem. Because a VM is really just a big file that looks like a disk, VM sprawl is storage sprawl.

Second, virtual servers have unique I/O performance characteristics. One big problem is the "VM I/O blender," in which disk I/O performance drops precipitously as VMs are added to a box and I/O-intensive applications are virtualized.

Third, virtual server storage management is more complex than for physical servers. Currently, it takes too much administrative time and is fraught with opportunities for mistakes. Storage management is integral with VM management, so the hypervisor needs a certain amount of integrated storage management.

Finally, a consistent complaint is the total cost of VM storage. Organizations go virtual to save money, but often, all the money saved on servers gets spent on extra storage, which is crazy.

InfoWorld: What are some of the challenges that Virsto is aiming to solve for Microsoft Hyper-V customers?

Davis: Our goal is to make virtual storage as empowering as virtual servers. That means making it easy to optimally provision VM storage without leaving the Hyper-V Manager console, enabling simpler backup, dramatically reducing the amount of disk space consumed by VM images, and improving the storage I/O throughput of Hyper-V servers. And we aim to do this with a small, simple piece of software that has no guest VM footprint and works with any storage hardware.

InfoWorld: What are some of the options we have had for solving these challenges?

Davis: Two choices. First, be less aggressive in adopting virtualization. That is, leave more applications on physical servers, and accept reduced consolidation benefits by running fewer VMs per box.

The second option is to overprovision storage. Buy more terabytes, spindles, I/O hardware, higher-end storage arrays, cache, and expensive software licenses. Ironically, virtualization helps us not overprovision servers, yet to achieve it we have to overprovision storage!

InfoWorld: Why start with Microsoft Hyper-V? Why not launch with VMware since it has the majority of the market?

Davis: Microsoft Windows Server 2008 Hyper-V R2 is rapidly gaining adoption. There are several compelling aspects to Hyper-V, yet there are opportunities for Microsoft partners like Virsto Software to add significant capability. The Microsoft platform is relatively easy to integrate with, Microsoft's organization has been a pleasure to work with, and customers adopting Hyper-V are looking for simple, low-cost storage solutions that unleash the full power of virtualization. That made it easy to choose Hyper-V as our launch platform.

InfoWorld: In that case, how long before your solution starts to support other hypervisor platforms, like VMware vSphere or Citrix XenServer?

Davis: Over 95 percent of our software code is independent of a particular hypervisor, and we run on multiple platforms in our lab. We intend to deliver exciting new storage solutions for all virtualization users.

The speed with which we release versions of our Virsto One software on other hypervisors will be a function of market demand and hypervisor platform vendor support. With help from other virtualization platform vendors, we could deliver new versions within a couple of quarters.

InfoWorld: With other storage virtualization solutions already out there, what do you consider your biggest differentiator?

Davis: The greatest flaw of alternatives is that they are built on foundations that aren't specific to virtualization. We are the only product that is built from the ground up specifically for virtual servers.

Thanks again to Mark Davis for speaking with me. Virsto One will be generally available by the end of February and pricing will be per server socket. The company is also offering a free 30-day trial to Microsoft Hyper-V users.

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