Startup solves Microsoft's Hyper-V storage problem

Startup Virsto increases VM density, stops server sprawl and decreases storage needs for Hyper-V

One of Hyper-V's biggest problems, the high cost of storage associated with VM server sprawl, is being fixed by an add-on product from Virsto Software, a storage virtualization startup with an all-star management team, in Sunnyvale, Calif.

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Hyper-V isn't the only hypervisor that puts a strain on storage, but (as VMware likes to point out) most users can't pack as many VMs onto a server with the nascent Hyper-V as they can when VMware runs the show. In other words, for most applications, VM density with Hyper-V is lower than it is with VMware. As the number of servers grow, the money saved on buying fewer physical servers is quickly spent on buying more storage.

The Virsto One storage virtualization software hopes to solve that problem, says CEO Mark Davis. "We reduce the amount of storage footprint of storage machines by 90% compared to deploying Hyper-V without us."If you looked inside the bits, started with one gold image, fired up 100 copies and ran them for a year, you'd find that almost all bits are still the same ... 80% maybe even 90% are the same. Yet you made a copy of all the bits, there's a copy of that same DLL in every instance."

With Virsto, the DLL, and all the other files common to every VM, will only get stored once. Virsto One then manages how each virtual machine accesses those same, shared files, so that each VM thinks the file belongs to it alone.

In addition, Virsto One ensures that read/writes are sequential, the fastest way to go. "If you ran a benchmark with one VM and it was x, and then you run 10 or 20 VMs simultaneously, you might get one-fifth of x -- or an 80% performance degradation of throughput of the box because of randomization," he says. "Random I/O is one to two magnitudes slower than sequential I/O."

With Virsto, Davis promises that even as you pack on the VMs, I/O performance will not degrade ... that running VMs on a server will be as speedy as running a single one. The products supports any block storage system including iSCSI, Fiber Channel, FCoE.

Virsto also promises to make provisioning of VMs lightening fast, saving time in the admin's day as it can create a "thinly provisioned" clone in a matter of minutes, since it doesn't create a copy of all the files that will be shared. And it doesn't allocate space on the storage system until the VM writes to it.

But Hyper-V's basic market strategy is all about being cheaper than VMware. Even the most ardent Hyper-V lovers admit that the hypervisor is at best comparable, and at worst, still behind VMware. It's not leapfrogging its competitor based on features. So, any add-on can't cost much -- or it kills Hyper-V's one big advantage ... price.

Virsto One charges on a per server model. It costs $1250 for a two socket server, and $2800 for a four-socket server (or larger). This gives you the perpetual license to the basic software with an annual maintenance fee charged for updates, ongoing support and the like. Plans are in the works to port Virsto One to VMware, too, and possibly XenServer and KVM as the need arises.

I can't testify that Davis claims of his product are accurate. I haven't personally tested the software (if you've played with it, please comment and let us know what you thought of it).

But the company does have a few paying customers and even more beta customers. These include a large hosting data center customer running Hyper-V to support cloud Exchange/Office services, Davis says. One customer notably missing from Virsto's list is probably the biggest Hyper-V user of them all ... Microsoft.

Even so, if you are considering moving from VMware to Hyper-V, but have been scared off by tales of lower VM density and higher storage costs, you might want to put Virsto One in the lab and (excuse the pun) give it spin.

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