When talking about Virtual SAN you hear a lot of people talking about the benefits, what Virtual SAN is essentially about. You see the same with various other so-called Software Defined Storage solutions. People typically, when talking about these solutions, talk about things like “enabling within 2 clicks”… Or maybe about how easy it is to scale out, or scale-up for that matter. How much performance you have because of the way they use flash drives. Or about some of the advanced data services they offer.
While all of these are important, when it comes to Virtual SAN I don’t think that is the true strength. Sure, it is great to be able to provide a well performing easy to install scale-out storage solution… but the true strength in my opinion is: Policy Based Management & Integration. After having worked with VSAN for months, that is probably what stood out the most… policy based management
What does this deep integration and what do these policies allow you to do?
- It provides the ability to specify both Performance and Availability characteristics using the UI (Web Client) or through the API.
- Number of replicas
- Stripe width
- Cache reservations
- Space reservations
- It allows you to apply policies to your workload in an easy way through the UI (or API).
- It provides the ability to do this in a granular way, per VMDK and not per datastore.
- To a group of VMs or even all VMs in a programmatic way when needed.
Over the last couple of months I have played extensively with this feature of VSAN and vCenter, and in my opinion it is by far the biggest benefit of a hypervisor-converged storage solution. Deep integration with the platform, exposed in a simplistic VM-centric way through the Web Client and/or the vSphere APIs.