Nasuni Gets $15M as Cloud-Storage Gold Rush Carries On

Natick, Mass.-based, cloud-storage startup Nasuni has closed a $15 million Series B round, led by Flybridge Capital Partners with participation from existing investors North Bridge Venture Partners and Sigma Partners. The company has raised $23 million over two rounds on the promise of its file system virtual appliance that automatically distributes files between the cloud and a local cache. We covered it in February, when its Nasuni Filer software entered public beta, and since then, it entered general availability and has been adding support on a regular basis to expand beyond its initial VMware-only scope.

I noted in February that although VMware (s vmw) is the predominant hypervisor in corporate data centers, it’s fast losing ground to alternatives. To address this, Nasuni has expanded its coverage to both Microsoft Hyper-V (s msft) and Citrix XenServer (s CTXS). Its Windows support actually goes beyond Hyper-V to include the ability to store files in Windows Azure and on-premise Windows Distributed File System namespaces. Aside from Windows environments, Nasuni also added support for Rackspace Files, (s rax) Nirvanix, EMC Atmos-based (s emc) platforms and private clouds, in general.

Nasuni’s virtual appliance form factor and file-system focus help distinguish it from other startups that have launched in the past several months, but the idea of a local appliance controlling data placement between local servers and the cloud is catching on. Cirtas and StorSimple, for example, sell physical appliances that send data to the cloud for backup but keep certain info local via built-in cache capacity. Both virtual and physical appliances have their benefits – virtual appliances are quickly downloadable and relatively inexpensive, whereas physical appliances offer better performance (StorSimple just added SSDs to its appliances).

Whatever, the approach, though, cloud storage startups are racking up funding. Nasuni’s $23 million total puts it a hair above scale-out storage provider Zetta at $22.5 million, but well below Nirvanix and its $45 million. Appliance comrades Cirtas and StorSimple have raised $10 million and $21 million, respectively, and clustered file system vendor Scale Computing just raised its total to $31 million.

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