VSAN-Troubleshooting-Reference-Manual

Diagnostics and Troubleshooting Reference Manual – Virtual SAN
2. What is VMware Virtual SAN (VSAN)?
VMware Virtual SAN is a new software-defined storage tier for VMware vSphere,
bringing the benefits of the software-defined data center to storage. By clustering
server magnetic disks and flash devices in hybrid condifurations, or many flash
devices in all-flash configurations, Virtual SAN creates a flash-optimized, highly
resilient shared datastore designed for virtual environments.
Virtual SAN aggregates the local or direct attached storage of ESXi hosts and makes
them appear like a single pool of shared storage across all the hosts. It introduces a
converged storage-compute platform – virtual machines are running on ESXi hosts
as per usual, while a small percentage of CPU and memory resources are used to
serve the storage needs of the same virtual machines.
Based on a hypervisor-converged distributed architecture embedded in the vSphere
kernel, Virtual SAN can make optimal data placement decisions and I/O
optimizations. Because Virtual SAN sits directly in the I/O data path, the product is
able to deliver the highest levels of performance, scalability, and resilience without
taxing the CPU with additional overhead.
Since Virtual SAN has a distributed architecture, virtual machines can be deployed
in a way that no single hardware failure will impact their availability.
Virtual SAN also differs from other storage products in its policy-based approach to
storage management. This management architecture enables administrators to
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