VMware announced the public beta of VMware Virtual SAN (VSAN) product during VMworld 2013, which stirred up considerable interest -- and some confusion.
Despite the use of the "VSAN" acronym, VMware VSAN differs from traditional virtual storage area networks (VSANs). A virtual storage area network is a logical partition in a storage area network (SAN). Traditional VSANs can isolate traffic within specific portions of a SAN. A VMware VSAN can be constructed to be independent of other VSANs, which adds both security and stability.
Rather than keeping resources separate, VMware VSAN is all about keeping them together -- and keeping it simple. The VSAN product is VMware's next piece in its push to construct the software-defined data center. VMware VSAN, integrated with the hypervisor starting with vSphere 5.5 and managed from the vSphere Web client, pools hard drives and flash storage from a cluster of ESXi hosts as a data store for virtual machines.
Another benefit to enterprises is cost; VSAN can be used with a company's existing storage, so long as it is on VMware's hardware compatibility list, without the need to buy additional hardware. VSAN uses solid-state drives for read/write caching and hard disks for primary storage.
VMware VSAN still emerging
While early reaction to VSAN has been generally positive, some users said it could use more storage management features and that it was doubtful it could replace a traditional storage area network. The VSAN product also could further blur the lines between virtualization administrators and storage administrators, which may lead to questions about the responsibility of provisioning duties.
Another caveat is IT shops that use multiple hypervisors such as KVM and Hyper-V will not be able to access the clustered storage that's created by VSAN.
While currently in beta and not recommended for production environments, a suggested use case for VSAN includes using it as a distributed storage layer for nonpersistent VDI.
The software requirements for VSAN include either vSphere 5.5 or vSphere with Operations Management 5.5 or vCloud Suite 5.5, and vCenter Server 5.5.