Apr 20, 2021

Comparing Storage Purchasing Models


Posted by

Howard Marks

VAST's Gemini represents a new go-to-market model for storage, taking elements from the traditional appliance, software-defined storage, and cloud-like pay-as-you-go consumption models. Let's take a look at how Gemini compares to those classic storage purchasing models.

Building storage arrays

Before we can really understand how storage vendors sell their wares we have to look at how storage systems are built today, especially for startups with a core competence in software, like VAST.

Legacy storage systems like EMC's Symmetrix were built around custom FPGAs and ASICs, but that sort of custom hardware has been largely eclipsed by software-defined storage (SDS), running on x86 CPUs. In the SDS era, storage systems are defined by their software. With a very few notable exceptions, storage systems today are assembled from the same essential parts:

  • Media drives

  • X86 servers

  • Network interfaces

  • Drive Shelves

It's easy to think of storage vendors as manufacturers running factories like Ford's legendary River Rouge plant where iron ore was delivered at one end and Model As rolled out the other. While some tech giants like Dell have actual factories, most tech companies concentrate on R&D and use OEM manufacturers to etch the circuit boards, bend the sheet metal and assemble their products. Most famously, while Apple does their own design, down to custom CPUs, but outsources manufacturing to China's Foxconn.

Storage startups for the past decade have based their systems on x86 based appliances and shelves from OEM's like SuperMicro, Xyratex, or like VAST Viking, turning them into block storage arrays, NAS appliances, and backup appliances with software.


While a storage startup could build a small warehouse/factory and assemble systems themselves, it's much more cost-effective to hire a contract manufacturer. Contract manufacturers have inventory, assembly, burn-in and shipping functions in place they can amortize across multiple customers, including those making security and other network appliances in addition to storage vendors. Traditional storage vendors negotiate prices with multiple suppliers to ship components to the contract manufacturer and pay their contract manufacturer fees for their services.

Comparing Gemini and The Storage Appliance Model

Before Gemini, VAST operated under the traditional storage appliance model. We bought high-density server appliances and SSDs from Intel, network cards from Nvidia's Mellanox division, and Viking Enterprise Solutions' enclosures. Those vendors all shipped their products to our contract manufacturer Avnet who integrated customer systems, burnt them in, and shipped tested VAST systems to the customer where the local VAST SE would install the system. An OEM license for VAST’s software was bundled with each enclosure

Under Gemini, the flow of goods is exactly the same. VAST negotiates prices with suppliers based on the collective volume of VAST customers. The suppliers send their products to Avnet, where they're integrated, burned in as a system, and shipped to the end customer.

The flow of responsibility under Gemini is the same as under the appliance model too. VAST's local SE still installs the system; VAST still answers all the support calls. VAST is still responsible for replacing failed components, even worn-out SSDs for any appliance running a Gemini subscription. Avnet provides parts depots and delivery services just as they did when we sold appliances.


The only thing that changes is the flow of cash. Back in the appliance model, VAST would buy components, carry the inventory cost, and sell the hardware to our customers with our markup added. Under Gemini, VARs buy hardware directly from Avnet, at the price VAST was paying, and Gemini subscriptions from VAST. Since we don't handle the hardware, we don't mark the hardware up either.

Under the old model we promised to write support contracts on any server appliance or enclosure for 10 years at a flat price regardless of whether a customer bought a 10 year support contract when they bought their hardware or if they want to renew every year. That applies to Gemini subscriptions too, VAST customers will not pay more for Gemini renewals 2 years, or 9 years later.

That also means that VAST customers pay the same price for expansions as they do for a big initial purchase. VAST customers buy hardware at cost, regardless of the size of the deal, and they pay the same price for Gemini subscriptions on the 2 enclosures they’re adding today as the do for the 15 enclosures they bought last year.

Software Defined Storage as a Go-To-Market Model

Unfortunately, marketers, like your not so humble author, have used the term Software-Defined Storage (SDS) to describe just about every kind of storage solution that included software over the years. Since we're discussing purchasing and go-to-market strategies, we'll limit our SDS definition to products sold as software to be run on hardware provided by another vendor like FreeNAS, VMware's VSAN, IBM/Red Hat's Gluster, and CEPH.

Compared to the traditional appliance model, software-defined storage frees customers from storage vendors' high markups, allowing customers to shop in the much more competitive market and, therefore, lower markup, server, and drive markets. More significantly, since customers buy software and hardware separately, those software licenses aren't tied to the hardware allowing customers to upgrade their hardware without re-buying the software.

While SDS is a step forward from the old appliance model, the SDS model has a few significant problems. Technically, SDS forces the storage software to adopt a least common denominator approach to components. If a software package has to run on any of 20 or more SSDs, the vendor can't afford to optimize their code for each; instead, they treat all those SSDs alike. VAST offers 10-year SSD endurance from QLC SSDs by shaping the writes we do to the QLC SSDs to align with the flash's internal structures in those SSDs to prevent the write amplification created when the SSD has to perform internal garbage collection. SDS vendors can't afford to support each SSD that specifically, instead they use more expensive SSDs with DRAM buffers and higher endurance.

Broad hardware support also creates problems for the software vendor, with each device on the Hardware Compatibility List (HCL) costing money to qualify and support. Even when a server, NIC, and each of the SSDs are on the HCL, customers will occasionally create unique combinations that interact to create problems the software vendor has never seen before.

The bigger problem with software-defined storage is that it shifts too much responsibility from the storage vendor to the customer. The customer is forced to make deeply technical decisions, from the SSDs to use at each storage layer to the CPU/Capacity ratio, without the deep knowledge of the software's internals a storage vendor would have. Responsibility also shifts; from the storage vendor as a single responsible party to the customer or their VAR for integration and troubleshooting. SDS customers can't rely on their software vendor to be able to duplicate their system to reproduce problems.

Reference architectures and OEM integrated appliances can partially address these problems, but even these leave room for finger-pointing over problem ownership and resolution.

Gemini and SDS

Gemini goes one step further than SDS in freeing users from high storage vendor markups by eliminating hardware markups altogether. Customers to buy their hardware directly from Avnet at the price VAST negotiates as our cost, leveraging our customer's aggregate buying power.

Gemini avoids SDS's disadvantages by limiting hardware choices to a very small number of well-understood configurations. A very small HCL empowers VAST to optimize the software for the specific behaviors of the Intel SSDs and Mellanox NICs we use and more significantly allows VAST to shoulder all the hardware and software support responsibilities. Gemini customers call, email, Slack, or otherwise contact VAST support with all their problems. No split responsibility, no room for finger-pointing.

Gemini for Customers

We at VAST designed Gemini with two goals in mind. The first was to shift VAST’s business model from hardware to software. Frankly investors value software companies higher than they do hardware companies and getting out of the business of selling hardware makes our investors current and future happy. The second, and no less important, was to free customers from the expensive norms of the storage business, like appliance locked OEM software licenses and higher costs for renewals. We think we’ve done a pretty good job at both. 

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