Since Hewlett-Packard acquired LeftHand Networks in 2008, it has continued to develop LeftHand's complete line of software-based iSCSI storage under the HP LeftHand P4000-series moniker. Based on the feature-rich SAN/iQ 9.5 software platform, the currently available P4000 G2 series includes a range of different physical form factors based on HP's ProLiant server line, as well as the virtualized P4000 VSA (Virtual SAN Appliance), which runs on VMware vSphere or Microsoft Hyper-V.
At its heart, the P4000 VSA is simply a virtualized (and thus hardware agnostic) version of the same SAN/iQ software that powers its physical brethren. Though the virtualized version comes with notable scalability limitations, it offers a great deal of flexibility in configuring storage either in concert with physical P4000-series SANs or on its own as a purely virtual SAN.
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Use cases for the P4000 VSA are wide and varied, including everything from utilizing direct-attached storage to implement redundant shared storage in small-business environments to allowing single-host remote offices to asynchronously replicate back to a headquarters site for disaster recovery purposes. Plus, given that the P4000 VSA can utilize any storage hardware supported by its host hypervisor, the VSA can be used to breathe new life into outdated or retired storage platforms, be they DAS-, NAS-, or SAN-based.