VMware VSAN: Intriguing But A Ways Off

While VMware’s official launch of its Virtual SAN (VSAN) drew positive responses from IT managers at last month's VMworld, adoption of the technology likely will be slow.

VSAN is a major part of VMware’s software defined data center (SDDC) initiative. VMware says VSAN addresses the need for a faster, more dynamic underlying storage infrastructure as virtual machine density has increased. The product is scheduled for general availability in the first half of 2014.

When asked about what caught his eye at the show, one IT manager responded: “VSAN. Anything they [VMware] can do to help me respond to our business faster is going to be a huge help.”

At the core of VSAN is the VSAN cluster, initially a group of three to eight compute nodes each with at least one SSD and one SAS disk drive. Each compute node can have a maximum of five disk groups consisting of an SSD and up to seven hard drives for over a half-petabyte of storage per cluster. The SSDs function as a read/write cache while the hard drives store VMDKs, swap files, and snapshots.

With VSAN, IT teams can dynamically provision storage resources much in the same way they can use server virtualization to manage compute resources. They can create storage policies for redundancy, performance and other storage attributes and apply them to applications and storage resources on demand without having to previously provision storage pools. Receive a request for a mission-critical database, for example, and apply a “database template” to configure compute resources plus your storage policy to define the maximum number of node failures in a VSAN cluster, percentage of flash read cache devoted for the database, and other rules.

Although IT managers expressed interest in VSAN at VMworld, they also indicated that actual adoption is at least 18 months away.

“I can see us having a line item in our budget for VSAN and SDDC towards the end of next year [or] the start of the following year,” the vice president of technology at one manufacturer told Network Computing.

[There was a lot of chatter during VMworld about combining VSAN with PernixData's FVP. Read what Howard Marks thinks of the idea in "A Bad Combo: PernixData's FVP and VSAN." ]

A data architect at a major energy company said his company would hold off on an immediate purchase. “I’m looking at SDDC, but we’re a pretty conservative company so I don’t see us actually deploying the technology until a 2.0 release," he said.

Even once VSAN is ready for purchase next year, IT will likely have some tough choices to make.

“The whole concept of software defined storage is something that I think has still to evolve, and I am not completely certain that VMware, as a virtualization company, knows how to do it better than a companies that are focused only on storage, ” said Maish Saidel-Keesing, a systems architect who runs the virtualization blog Technodrone.

Those companies are numerous, spanning traditional storage providers as well as new virtualization storage vendors such as Nutanix, and cache vendors such as PernixData.

Do you want to know how the shift to software defined networks might impact your job? Check out the panel discussion Will SDN Make Me Homeless? at Interop New York in October.