Wednesday, May 24, 2017

Thoughts on HyperConverged, and the Future of HyperConverged (Part 2)

So how did we get here? Where did HCI come from?

If we look back at the history of HCI, it seems to have evolved from the idea of using clustered, "whitebox" x86 servers to create a clustered storage system. There were a number of early entrants in the space, some dating back to 2006. Another vector was the idea of a "Virtual Storage Appliance" or VSA, software which ran in a VM, connected to local server hard disk drives, and presented that internal storage to the guest VMs over the internal IP network. The first VSA was from Lefthand in 2007. But the real hyper-converged push started around 2009 with the founding of integrated HCI players Nutanix and SimpliVity.

We also have to look at where the HCI market is today. It is arguably dominated by three primary players: Nutanix; SimpliVity (now part of HPE); and VMware VSAN. They represent the lion's share of the HCI market, and we will come back to them.

If you look at the earlier clustered storage companies, they either offered a scale-out NAS, a kind of commodity alternative to Isilon, a scale-out block storage solution, or a scale-out unified storage solution. These early players came into existence when "grid computing" was the buzzterm of the day, and these architectures were also called "grid storage".

In 2009 Nutanix was founded. There were other virtual storage appliance start-ups, such as Virsto Software (which eventually became VMware VSAN), but it is fair to define the official beginning of the hyper-converged era as August 2011, when Nutanix emerged from stealth. The same month, VMware released vSphere 5 which included its first implementation of a VSA (vSphere Storage Appliance). SimpliVity would emerge from stealth one year later in August 2012. VMware's VSA did not gain traction, and VMware announced its intent to acquire Virsto six months later in February 2013 which represented VMware's serious interest in HCI.

As Nutanix and SimpliVity started to grow, and with VMware's very public acquisition of Virsto, and obvious plans to enter the HCI market, many of the earlier clustered storage vendors and virtual storage appliance vendors redefined themselves as hyper-converged players. Several new industry buzzterms were developed: "Server SAN"; "Virtual SAN"; and "Software Defined Storage", or "SDS".

Many of the early clustered storage system vendors redefined themselves as SDS or HCI players, moving their clustered storage software from bare-metal to run in VMs, and allowing their clustered storage software to run alongside guest VMs on the same server. VSA vendors added more sophisticated clustering, replication, and scalability to their products.

From this, it is fair to say modern HCI owes itself to three parents: Commodity clustered storage systems; virtual storage appliances; and purpose built integrated HCI systems.

To me, the most interesting thing is many of the earlier clustered storage or "grid storage" players had little to no success, but the HCI players saw significant early success. Part of this may have been how each targeted the market. Clustered/grid storage historically had been seen as targeting the high-performance and academic community for technical computing use cases. HCI targeted business organizations and VMware virtualization workloads.

But what cannot be dismissed is the reality the early clustered storage ystems did not provide the level of performance and reliability required for enterprise workloads. The early clustered storage systems were not designed for transactional, random I/O workloads. They were better suited for sequential I/O. The early HCI players focused on addressing write latency and random I/O with aggressive write and read caching. The also focused on ease of use and eliminating the need for storage administrators to provision storage to VMware administrators.

At this point it is interesting to note, there were other players aggressively targeting VMware virtualized workloads. Tintri had come out of stealth five months before Nutanix with its VMware optimized storage platform. It too targeted the VMware admin and sought to used its product to bypass the traditional storage management team in an organization.

So that is the history lesson and the end of Part 2.

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