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Virsto Citrix Storage Hypervisor Addresses VDI Performance, Costs

Posted by Esther Shein
May 10, 2012

Virsto Software has come out with a storage hypervisor software product geared at Citrix’ XenDesktop virtual machines that it claims will increase performance and efficiency, and ease virtual desktop provisioning and patching.

Provisioning storage in virtualized environments typically requires a choice between production-level performance or efficient storage capacity consumption. In the same way hypervisors changed servers in virtualized environments, Virsto is looking to change storage. The hypervisor software approach reduces the cost of storage for VMs by as much as 50%, the company says.

The term storage hypervisor is not generally accepted currently in the IT industry, as only two smaller companies--DataCore and Virsto--in addition to IBM, seem to be advocates of the term, says analyst David Hill. IBM believes the storage hypervisor is a combination of application software that performs the necessary storage virtualization functions, and management software that provides the centrally, automated framework for all virtualized storage resources.

Designing a cost-effect storage infrastructure is extremely challenging in a VDI environment, and can run in excess of $1,000 per desktop, notes Simon Bramfitt, founder and principal analyst at Entelechy Associates. While he says the term "storage hypervisor" is "stretching the boundaries a little of what you can legitimately call a hypervisor," he adds, "It’s only when we start using this sort of hypervisor storage optimization that we can get cost down to acceptable levels." Hypervisor storage software makes it possible to bring the cost of storage down to less than $200 dollars per desktop, depending on the product and vendor arrangement, he says.

Server virtualization projects often result in new problems with storage capacity utilization and performance due to the physical server trying to use its limited resources to handle a much heavier randomized I/O workload, notes Hill. The Virsto Storage Hypervisor takes the pain out of one of IT’s thorniest current problems VDI, or virtual desktop infrastructure, by addressing both of these issues.

The software essentially is a virtual appliance that offloads storage activities from a SAN to support VDI environments, where the storage requirements are more focused on throughput than actual capacity. "By moving it closer to where the workload is, it significantly improves storage system performance as well as reducing costs," Bramfitt says.

Right now, the only way to achieve the necessary throughput to support a VDI environment is by using high-performance, high-memory flash drives, or to scale storage out using a lot more disk drives, he says. Products like Virsto’s means IT doesn’t have to take either approach; instead of having a high-performance flash disk, the controller is using server memory to do the same thing.

"Actual straightforward server memory is significantly less expensive than the flash memory the controller would use," Bramfitt says. "And because you’re using ... conventional server memory and server processing power ... you’re getting extremely high storage throughput." That means not having to use a lot of additional disks.

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