VMware’s vSAN vs. Traditional Shared Storage

The storage world has been changed forever by the cloud, just as many other traditional IT offerings. VMware relaunched a key component to its software-defined data center puzzle with a virtual SAN product, aptly-titled Virtual SAN that seeks to scale resources and simplify management.

The traditional server market has consistently delivered resilient, feature-rich products that produce solid storage performance. Shared arrays have also seen technological advances to better tie into the server virtualization layer by providing direct access to the storage management firmware. vSAN is an advanced storage solution that builds on the groundwork of its predecessor product - VSA - by providing a greater level of flexibility, scalability, performance, and ease of management. Additionally, it provides features similar to thin-provisioning and garbage collection at the storage system through a programming extension called VAAI.

While the main focus of vSAN is to move customers away from needing shared physical storage, it effectively serves to also transfer the responsibilities of dealing with storage systems from the company’s storage group to the server group. The overall trend in storage is to see features that were once only available on very high-end enterprise storage products move to the server software layer: snapshots, caching and storage tiering, deduplication, and encryption. These features are now available at price points that small to medium businesses can stomach.

By comparison, vSAN is still a fairly new product and many of the advanced features that customers would like are not available yet in vSAN 1.0. The initial release does not support vSphere Fault Tolerance, Storage Distributed Resource Scheduler, Storage I/O Control, or Distributed Power Management. There is also the not-so-unimportant matter of scalability, which at this time, vSAN does not address. Since vSAN runs off of local storage, optimizing local storage performance is more important than ever when considering the switch from traditional storage products to server software-based storage offerings.

Yesterday’s hardware-defined world is being replaced by tomorrow’s software that is storage agnostic. Along with other software companies in this space, VMware’s reinvention of traditional storage makes many storage conservatives a little nervous and is sending storage vendors into an outright panic in some cases. This is yet another impact of the workload abstraction that is taking place through server virtualization, and as these changes ripple through the IT storage layer, vendors of traditional storage need to find new ways to provide value.

While the industry is not yet ready for the storage migration that is impending, now is the time to evaluate long-term business goals and make infrastructure decisions that will have serious impact on the budget of IT departments.