Here is a brief excerpt from the newly released Second Edition of Essential Virtual SAN (VSAN): Administrator’s Guide to VMware Virtual SAN by Cormac Hogan and Duncan Epping, VCDX #7 from VMware Press.
Introducing Virtual SAN
VMware’s plan for software-defined storage is to focus on a set of VMware initiatives related to local storage, shared storage, and storage/data services. In essence, VMware wants to make vSphere a platform for storage services.
Historically, storage was something that was configured and deployed at the start of a project, and was not changed during its life cycle. If there was a need to change some characteristics or features of the logical unit number (LUN) or volume that were being leveraged by VMs, in many cases the original LUN or volume was deleted and a new volume with the required features or characteristics was created. This was a very intrusive, risky, and time-consuming operation due to the requirement to migrate workloads between LUNs or volumes, which may have taken weeks to coordinate.
What Is Virtual SAN?
VSAN is a storage solution from VMware, released as a beta version in 2013, made generally available to the public in March 2014, and reached version 6.2 in March 2016. VSAN is fully integrated with vSphere. It is an object-based storage system and a platform for VM storage policies that aims to simplify VM storage placement decisions for vSphere administrators. It fully supports and is integrated with core vSphere features such as vSphere high availability (HA), vSphere distributed resource scheduler (DRS), and vMotion.