Solution Providers Embrace Virtualized Storage Appliances

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Unlike physical appliances, which include an application and the operating system installed on a specific piece of server hardware, virtual appliances are prebuilt, preconfigured software bundles that include the application and operating system and are designed to be downloaded onto a virtual machine. This lets ISVs configure and harden their applications without regard to the underlying hardware.

Virtualized storage appliances have become available from a variety of vendors, most of which make them available for downloads into virtual machines built using VMware's ESX Server application. VMware hosts a site from which the majority of those appliances can be downloaded.

The move to adopt virtualized storage appliances in lieu of hardware appliance counterparts is driven by customers who see the benefits of virtualization and are looking to embrace it as quickly as possible, said Steve Bishop, CTO of VeriStor Systems, an Atlanta-based storage solution provider.

"Savvy customers with virtualized environments are looking to virtualize everything they can," Bishop said. "They look at commodity appliances, and think there is a better way to do it."

For many of those customers, there is. Removing the hardware component and turning a storage appliance into code that can be downloaded into a virtual machine cuts the cost of the storage appliance and makes it easier to quickly deploy and redeploy for testing and evaluation purposes.

However, there is a serious trade-off: performance. Virtual storage appliances offer noticeably lower performance than similar hardware-based appliances. But for small or midsize customers or remote offices, where performance requirements may not be an issue, the trade-off may be moot.

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Lefthand Networks, Boulder, Colo., is shipping its Virtual SAN Appliance (VSA), a virtualized version of its SAN/iQ software. SAN/iQ turns any server into an iSCSI SAN node. As multiple SAN/iQ nodes are clustered, capacity and performance both scale, said Adam Carter, technical products manager for the company.

The VSA, when downloaded onto a VMware virtual machine, forms an iSCSI SAN node within a VMware ESX server. Each node can access up to 2 Tbytes of the server's internal storage for use in the SAN, with multiple nodes tied together over the LAN to combine capacity and introduce replication and redundancy. It does everything SAN/iQ does, except it has half the performance and a much more limited range of SAN monitoring capabilities, Carter said.

Using VSA to build a SAN based on virtual machines has huge implications for server virtualization because of the server-storage tie, Bishop said.

"To fully leverage all the VMware infrastructure, you need a SAN with a cluster of VMware ESX-based servers to do things like VMotion [moving a virtual machine from one physical server to another]," he said. "But for many smaller and midsize customers, the cost and complexity of a SAN pushes virtual server infrastructures out of their reach."

Also on board is FalconStor Software, Melville, N.Y., with two virtualized storage appliances. The first, the FalconStor Continuous Data Protection Virtual Appliance for VMware, eliminates the need to restore lost data by ensuring data is always available, according to the company. FalconStor designed the CDP appliance to be downloaded and running within 10 minutes. Changes to data tied to physical servers can be continuously backed up to another physical server or to a virtual server so if the production server crashes, the image for that server can be seamlessly restored to another physical server or to a virtual server. Virtual server data can be continuously protected to another virtual server for instant restores as well, he said.

Adam Bari, managing director of IPM, a New York-based solution provider that works with both VMware and FalconStor, said the virtual CDP appliance means solution providers can now start selling virtual storage appliances instead of hardware-only solutions. The solution is especially suitable for doing CDP with data stored in remote offices, Bari said. "FalconStor has taken a very unique approach to the CDP market," he said. "We look forward to working with FalconStor to make money on this."

Greg Knieriemen, vice president of marketing at Chi, a Cleveland-based FalconStor and VMware partner, said he has seen strong interest in the virtual CDP appliance. "The big pull is that it's a unique product," Knieriemen said. "As far as I can tell, it's the only solution for CDP that gives instantaneous data recovery, and at an attractive price point."

FalconStor also introduced the FalconStor VTL Virtual Appliance. Virtual tape libraries, or VTLs, are disk arrays configured to look to the host server and the backup software as if they are physical tape libraries. Data is streamed to and recovered from the VTL as if it were tape, so no changes are needed to the backup process. It includes FalconStor's Single Instance Repository de-duplication technology, which removes duplicate information as data is backed up or archived.

Knieriemen said a VTL could help open the market for replacing tape with disk-based storage.

"We're selling VTLs to SMBs and enterprises, across the board," Knieriemen said. "It's a 50-50 split. But there's a much larger base of SMB customers. The SMB adoption of VTLs is still marginalized. This could really open the door for VTLs in the SMB market."

VMware and several technology partners have other virtual storage appliances available for download.

Companies that have built virtual backup and restore appliances include RestoreVM from Holonyx, Loveland, Colo.; the ElasticDrive from ElasticDrive, Toronto; Arkeia Network Backup from Arkeia Software, Carlsbad, Calif.; and the Virtual Solution Box from Switzerland-based aeXia.

Other virtual storage appliances include the Trellis NAS Bridge Appliance, a NAS virtualization appliance for multiple CIFS and Unix servers from the Department of Computing Science of the University of Alberta in Edmonton, Alberta, and the FreeNAS NAS server from www.freenas.org.

In the end, virtualized storage appliances will only continue to grow in importance, Bishop said. "Because VMware and storage are too tightly integrated," he suggested, "customers either want their storage integrator to do VMware, or their VMware integrator to do storage."