10 Architecture & ROI Mistakes in the Post-VMware Exodus | SIXE

Mistake 01 of 10

Confusing urgency with strategy

Broadcom’s acquisition of VMware in November 2023 for $61 billion triggered the biggest upheaval in enterprise virtualization in over a decade. And “upheaval” is putting it mildly. Perpetual licences eliminated, ~8,000 SKUs consolidated into 4 bundles, a 72-core purchase minimum and reported price increases ranging from 150% to 1,500%. Tesco filed a £100 million lawsuit. Fidelity warned of risks to 50 million customers. Safe to say, the landscape encouraged a stampede.

And that’s exactly what happened: a lot of people have been running — just not always in the right direction. A CloudBolt survey (2026) found that 63% have changed their migration strategy at least twice (yes, twice). Gartner estimates VMware’s market share will fall from 70% to 40% by 2029, but the road there is full of twists that deserve considerably more thought than they’re getting.

Mistake 02 of 10

Ignoring open source project governance

Not all open source is created equal — far from it. The most relevant difference for a long-term business decision isn’t the licence, but something almost nobody checks: who controls the project and what mechanisms protect the community if commercial priorities shift.

Proxmox Server Solutions GmbH is a private Austrian company with €35,000 in share capital and an estimated team of 14–24 people. Great people, no doubt, but there’s no independent foundation, no open governance board, and no community representation in development decisions. In other words: the future of your virtualization platform depends on a single company’s choices.

Compare that to the MariaDB Foundation, where no single company can hold more than 25% of board seats — a safeguard that protected the project when MariaDB Corporation was acquired by K1 in September 2024. Or OpenStack, now under the Linux Foundation, with governance distributed across hundreds of organisations. Now that’s a safety net.

Mistake 03 of 10

Not reading the Contributor Licence Agreement

We know — reading a CLA isn’t exactly a Friday night plan. But it’s worth it. The Proxmox CLA grants the company a perpetual, worldwide, irrevocable licence over all contributions, with the right to relicence them under commercial or proprietary terms. This mechanism isn’t inherently problematic, but it’s exactly the structural combination (single company + AGPL + permissive CLA) that preceded every major licence change of the past seven years. It’s like watching storm clouds gather and saying “I’m sure it won’t rain.”

See the pattern? It’s pretty clear: no project backed by an independent foundation has ever suffered a unilateral licence change. Not a single one. This fact should inform any risk assessment, regardless of which platform you’re considering.

Mistake 04 of 10

Assuming subscription costs will stay flat

Every company that develops open source software needs to monetise its work, and that’s entirely fair — nobody works for free. The question isn’t whether prices will go up (they will, as with everything), but whether you’re factoring that into your TCO model.

Proxmox’s Community subscription went from €49.90 to €120/year (~140% increase), and in January 2026, all tiers rose another 3.8–4.3%. The new Proxmox Datacenter Manager requires at least 80% of nodes to carry Basic or higher subscriptions (€370+/socket/year). Sound familiar? It does to us, too.

OpenStack, Ceph and other VMware alternatives also have their own cost structures. No platform is free in production — if anyone tells you otherwise, smile politely and ask for the receipt. The real difference lies in which costs are predictable and which hinge on unilateral decisions.

Mistake 05 of 10

Underestimating the operational complexity of OpenStack

Let’s give credit where it’s due: OpenStack runs in production with over 45 million cores at organisations like Walmart, GEICO and LINE Corp. Its governance — now under the Linux Foundation — is among the strongest in the ecosystem. These are genuine, weighty advantages.

But (there’s always a but) the project itself acknowledges that 44% of IT vendors and 39% of enterprises report difficulty finding qualified professionals. The platform comprises over 30 service projects. Deploying and operating that stack requires teams with distributed systems experience that most VMware teams don’t have — not for lack of talent, but because these are fundamentally different skill sets. It’s like asking a brilliant Mediterranean chef to compete in a sushi championship: both are world-class cooking, but the skills don’t transfer automatically.

Mistake 06 of 10

Assuming Ceph is “just tick the checkbox”

Ceph is powerful and runs in production at impressive places: CERN, Bloomberg and DigitalOcean, among others. But the gap between a hyperscale Ceph cluster and the typical 3–5 node deployment in a VMware migration is like the gap between flying an Airbus and a microlight: both fly, but the rules are very different.

StarWind benchmarks in Proxmox HCI environments showed Ceph reaching 270,000 IOPS in mixed 4K workloads, compared to 1,088,000 IOPS for LINSTOR/DRBD and 1,199,000 for StarWind VSAN. And the risks of small clusters deserve close attention: losing one node in a 3-node cluster with 3x replication can leave the system in read-only mode. Not exactly what you want at 3 AM on a Monday.

Alternatives worth considering include LINSTOR/DRBD with near-native performance, StorPool with sub-100 µs latencies, and IBM Storage Virtualize with proven enterprise integration. Each has its strengths, limitations and expertise requirements.

Mistake 07 of 10

Not auditing the enterprise features you’ll lose

VMware has spent over a decade building capabilities that many organisations have baked into their operational workflows. They’re the sort of things that “just work” — until they’re gone. And when they disappear, the impact goes well beyond technology.

None of these limitations invalidate the platform — let’s be clear about that. But each one represents a gap you’ll need to fill with engineering, tooling or consultancy, and every workaround carries a cost that belongs in your financial model. Pretending they don’t exist is a recipe for unpleasant surprises.

Mistake 08 of 10

Calculating ROI on the licensing line alone

The licence savings are real. But presenting those savings as the project’s ROI is like valuing a house move solely by the cost of the van: technically correct, practically incomplete.

Gartner estimates migration services cost between $300 and $3,000 per VM. 44% of organisations experience unplanned downtime during migration. And projects estimated at 6 months routinely turn into 24 — a pattern that’s by now very well documented.

Mistake 09 of 10

Designing for Day 1 and ignoring Day 2

The migration is just the beginning — the honeymoon, if you like. The real cost shows up in day-to-day operations, year after year.

Cybernews found that many organisations that migrated to Proxmox aren’t keeping up with security updates. It’s understandable: when all the effort goes into migrating, it’s easy to forget that afterwards you still have to operate. At scale, the UI becomes unresponsive with several thousand VMs, and pmxcfs hits its limits around 11,000 VMs.

Mistake 10 of 10

Thinking that technology is the decision

Migrating away from VMware isn’t a technology project: it’s an operational transformation that touches people, processes, vendors, budgets and risk. Technology matters, of course. But it’s just one piece of the puzzle.

The VMware migration isn’t a technology problem. It’s an operational decoupling problem disguised as a technology problem.— Keith Townsend, The CTO Advisor

The questions that actually matter: what level of governance risk is acceptable to us? Do we have the team we need — or can we upskill in time? What’s our real TCO at 5 and 10 years? How do we protect our investment if the open source project changes course? Which workloads do we migrate first, and which ones should perhaps never move? And who will be our technical partner when things don’t go as planned? (Because at some point, they won’t. That’s life.)