VMware VSAN 6.2 Focuses on Greater Efficiency

Deduplication and compression is the star of the release.

In a week full of VMware announcements around desktop- and application-related virtualization products, the announcement of a point upgrade of its software-defined storage (SDS) technology has taken a back seat. But for those using VMware Virtual SAN (VSAN), the upgrades are worth noting.

The top enhancements in VSAN 6.2 are built around saving storage space. They include the addition of deduplication and compression, and an expanded offering that saves on disk space for RAID configurations.

Dedupe and Compression
VMware claims that the deduplication and compression technologies in VSAN 6.2 can "Reduce storage footprint and capacity costs with up to 7x storage efficiency while having minimal impact on CPU and memory overhead." One significant drawback is that it only works on all-flash storage arrays, so hybrid storage environments can't use it.

Duncan Epping, VMware's Chief Technologist, Storage & Availability, said on his popular blog Yellow-Bricks that customers have waited a long time for this upgrade: "Deduplication and Compression has probably been the number one ask from customers when it comes to features requests for Virtual SAN since version 1.0."

Deduplication and compression is enabled on the cluster level, Epping said. He added that VMware's internal testing has seen space savings between two and seven times, with the maximum savings being seen in "full clone desktops." At the lower end, with a savings of double, were SQL databases. "Results in other words will depend on your workoad(sic)," Epping wrote.

Erasure Coding
The next technology for increasing storage efficiency is erasure coding. This has to do with fault tolerance (FT), and how RAIDs are set up. With the new RAID-5/6 erasure coding, the amount of space needed for FT declines by a factor of two. In Epping's example, a standard 100GB disk FT setup using RAID-1 (mirroring) would need 300GB of disk space; with RAID-5/6, that number drops to half, or 150GB.

It should be noted, however, that erasure coding also requires the use of all-flash storage. This is likely to disappoint some customers, as few enterprises are using all-flash-only storage. Most have a mixture of flash and standard magnetic disks. In fact, VMware has touted VSAN in the past as a good solution for those types of hybrid environments; in this case, they won't be able to take advantage.

The other VSAN 6.2 upgrades include Quality of Service improvements, including the ability to manage IOPS on a per-VM basis, and support for SAP applications.

Moving Toward the Software-Defined Datacenter
VSAN is built into the vSphere kernel itself, and requires nothing more than checking a box and clicking "OK" to use. It's a key part of VMware's software-defined datacenter (SDDC) vision, in which compute, networking and storage work together to orchestrate the most efficient use of resources on a workload-by-workload basis.

VSAN 6.1 was released last August. Its main features were the ability to use it across geographically diverse sites, including Remote Office/Branch Office (ROBO).

VMware says that version 6.2 is expected to become available in Q1 2016. VSAN pricing starts at $2,495 per CPU, while the VSAN for Desktop list price starts at $50 per user.

About the Author

Keith Ward is the editor in chief of Virtualization & Cloud Review. Follow him on Twitter @VirtReviewKeith.


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