We recently tackled a tricky scenario – downsize a production vSAN cluster from 4-Node to 2-Node with witness node and moving to a new VVF licensing model.
Here’s the breakdown of the challenge and the solution we developed.

The Starting Line and the Roadblocks

Our customer had an existing 4-node vSAN Cluster (version 7.x, Original Storage Architecture – OSA) and wanted to shrink it down to a 2-node vSAN Cluster with a Witness Host, while simultaneously shifting to their newly purchased VMware vSphere Foundation (VVF) subscription license.

Roadblock 1: The Migration Method

VMware recommends the safest way to reduce a 4-node cluster to 2 nodes is via an intermediate step: converting the 4-node cluster into a Stretched Cluster first, and then removing the two unnecessary nodes.

The Problem: The customer’s existing vSAN Advanced (Perpetual) license does not support Stretched Cluster or 2-Node Cluster configurations. This blocks the recommended migration path.

Roadblock 2: The New License Capacity

The customer’s new VVF subscription includes vSAN capacity, but only for a specific amount (X TiB). To perform the required intermediate step of creating a 4-node Stretched Cluster, they would temporarily need to license the total capacity of all four existing nodes (XX TiB)—a much larger amount than what their new VVF license covers.

The Solution: Leveraging a Full Trial License

The core plan became: Upgrade to vSAN 8.x first, and then use the VVF license for the final 2-node cluster. The major hurdle was securing enough temporary licensing capacity for the required 4-node Stretched Cluster interim step.

Step	Action and Rationale
The Upgrade Pre-Check	The default 60-day vSAN Evaluation period is insufficient, as it does not support vSAN Stretched Cluster features. This option is out.
Secure Full Trial License	The customer must request a special 90-day vSAN Trial License through Broadcom portal. This trial license includes all full features, crucially, vSAN Stretched Cluster support.
Customer Trial Request	The customer must follow the official Broadcom Trial Request Workflow [https://knowledge.broadcom.com/external/article/367474/broadcom-trial-request-workflow.html ] from their own support account. They must specify that they require licenses covering the full temporary capacity (XX TiB).
Execute Migration	Once the 90-day trial license is applied to the 4-node cluster: Upgrade to vSAN 8.x -> Convert to Stretched Cluster -> Remove 2 Nodes to finalize the 2-Node Cluster + Witness setup.
Apply Final License	Once the cluster is successfully reduced to 2 nodes, the 90-day trial license must be removed. The permanent VVF-included vSAN license (X TiB) is then applied to the now-smaller cluster.

Note on Trial Licenses: Customers are generally limited to one request for a full trial license to cover unique situations like this. The license request typically has a turnaround time of less than one business day.

This approach ensures the migration is performed using the safest, supported method (Stretched Cluster intermediary) without requiring the customer to purchase excess permanent licenses they will only use for a few days.