VSAN SizingOne of the most discussed topics about Virtual SAN has been around its scalable architecture design and the ability to scale up and scale out. In this article, I want to discuss and showcase the scale up capabilities of Virtual SAN.

Virtual SAN’s disk support is based on hybrid disk model that uses flash and magnetic disks to provide performance and storage capacity. Magnetic disks are the only disks devices that count towards the usable storage capacity of the Virtual SAN datastore. Flash devices compose the caching layer (read cache, write buffer). The Virtual SAN scale up methodology can be achieved in two different methods:

  •  Capacity
  • Performance

Scaling the storage capacity in Virtual SAN can be achieve by simply adding more magnetic disks to an existing disk group or by creating entirely new disk group. Virtual SAN supports up to 5 disk groups per host and each disk group supports up to 7 magnetic disks and one flash based device.

Scaling the performance layer (flash layer) of Virtual SAN is achieved in a similar way to scaling the storage capacity in the sense that you can quickly select the necessary disk devices and create a disk group. Virtual SAN disk groups require a minimum of one flash based device and one magnetic disk. In order to scale the performance of a Virtual SAN cluster, you will need to add a flash based device and at least one magnetic disk.

Either way you choose to scale up the Virtual SAN cluster for performance or capacity, the process and procedures is radically simple. Virtual SAN introduces one of the most costs effective and operationally efficient scaling models today.

The Virtual SAN storage scale up procedure is demonstrated in the video below.


– Enjoy

For future updates, be sure to following me on Twitter: @PunchingClouds

About the Author

Rawlinson Rivera

Rawlinson is a Principal Architect working in the Office of CTO for the Storage and Availability Business Unit at VMware. Focus on defining and communicating VMware’s product vision and strategy, and an active advisor for VMware's product roadmap and portfolio. Responsibilities revolved around connecting VMware's R&D organizations with customers and partners in the field. He specializes in enterprise architectures (private and public clouds), Hyper-converged Infrastructures, business continuity / disaster recovery technologies and solutions including Virtual SAN, vSphere Virtual Volumes, as well as other storage technologies and solutions for OpenStack and Cloud-Native Applications. Rawlinson is a VMware Certified Design Experts (VCDX#86) and main author of the blog