The CPU and Memory Economics of vSAN

Converged infrastructure lets an organization amortize the cost of compute, memory, and storage across a fleet of servers. Every server contributes all three resources to a shared pool, and every workload draws from that pool. That amortization matters more now than at any point in the last decade. Data center inflation is hitting organizations of every size, with server DRAM prices nearly doubling since late 2025 and flash capacity costs more than tripling in a year. Every core and every gigabyte of RAM in the data center needs to earn its keep.

Server virtualization is the best-known example of this amortization. VMware built its business on server utilization and consolidation, running dozens of workloads on a host that once ran one. The consolidation stopped at the storage tier. vSAN arrived years after vSphere, and its post-launch limitations kept many customers away. Those customers instead adopted three-tier architectures with dedicated all-flash arrays.

A dedicated all-flash array is the exact inverse of efficient utilization. Its controllers use RAM as cache, but their CPUs sit mostly idle, and applications in a typical data center never push the array close to its maximum performance. All-flash array vendors claim to be software companies, and they are. They ship a pair of servers prebuilt to deliver storage services, and customers pay for processors and memory that spend most of the day waiting.

Data center inflation makes that idle capacity expensive. This is the wrong time to buy more hardware, and it is certainly the wrong time to buy three times as many servers as you need and watch most of them sit idle.

Consider a midsize enterprise running a traditional three-tier architecture. The organization needs six physical servers to run its applications. Storage adds two more. Today’s array controllers are standard x86 servers running the vendor’s storage software, so a dual-controller array raises the server count to eight before anyone counts the shelves that hold the media. Networking adds a collection of appliances, each one a server underneath, running routing, firewall, and VPN services. That is three sets of servers, each sized for its own peak and each running far below it most of the day.

Switch the same organization to legacy vSAN and the storage controllers go away, but the virtualization hosts have to grow. vSAN is a set of separate software packages hidden behind a single GUI, and each package claims host CPU and RAM. Broadcom documents both the CPU overhead vSAN places on every host and a per-host memory footprint that grows with capacity. The cores and memory vSAN consumes are resources applications cannot use, so the cluster needs more servers, or larger ones, to run the same workloads.

Most vSAN deployments also have very limited networking capabilities. Routing, firewall, and microsegmentation require NSX, which is another purchase, another cluster of management VMs, and another claim on host resources. vSAN moves the storage tax off a dedicated array and onto the hypervisor hosts. The midsize enterprise still pays it, now in extra cores and DIMMs bought at today’s memory prices.

VergeOS makes a single set of servers work harder by integrating virtualization, storage, and networking into a unified infrastructure operating system. All three run in one codebase, so no separate products compete for host resources, and no infrastructure VMs need feeding. The first VM you create is yours.

Run the same midsize enterprise on VergeOS and the server count drops from eight or more servers to five. A single operating system that runs compute, storage, and networking in one codebase spends far less CPU and RAM on itself than a stack of separate products, so the workloads that needed six application servers run on five, and those five servers run the entire data center. VergeFS pools the drives inside those servers into shared storage, so you can remove the array controllers and shelves. Routing, firewall, and VPN run inside VergeOS virtual networking, so you can remove the network appliances and avoid buying NSX. Global inline deduplication reduces the data written to disk and the data held in RAM, stretching the flash and memory the organization already owns.

Instead of three sets of servers at a fraction of their capacity, the organization runs one smaller set of servers at high utilization, and every core and DIMM it paid for does work for its applications. VergeOS also supports almost any server built in the last ten years. Hosts coming out of vSAN service can stay in production, which removes hardware purchases from the exit plan, and the server freed by the consolidation becomes spare capacity for growth.

The unification into a single code base also delivers a step-function improvement in infrastructure management. Compute, storage and networking share one interface and one update cycle, which makes day-two operations simpler. IT generalists run the whole environment without separate storage and networking specialists, and a midsize team of three to five gets back the hours it used to spend coordinating separate compute, storage and network products.

Data center inflation changes how a vSAN exit should be evaluated. The hypervisor license is the visible cost. The hidden cost is the CPU and memory consumed by storage and networking layers that each run as separate software on hosts you paid for, at a time when every DIMM costs nearly twice what it did a year ago. Moving to another architecture that splits the work across separate tiers repeats the same waste with a new vendor’s name on it. VergeOS puts compute, storage and networking on five servers, about 20% fewer than the six application servers alone, running at high utilization, and it lets the organization keep the hardware it already owns.