A licensing renewal the board would not sign, turned into 140 VMs on open source
VMware → Proxmox VE + Ceph migration
Where they started
The virtualisation renewal arrived with a cost increase the business would not approve, and the team had no validated alternative — only a slide deck promising one.
The problem, precisely
The migration had to be reversible per wave, and no application owner would accept a weekend of unplanned downtime.
What we did
Modelled the replacement platform first, then migrated in four batches ordered by blast radius — starting with internal tooling so the team could make its mistakes where they were cheap.
Delivered
- Hyperconverged platform with SSD and HDD pools and a documented failure-domain map
- Per-wave rollback rehearsal: every VM restorable to the old platform within the window
- Licence cost comparison table for the board, including support and training lines
- Application-owner sign-off checklist with an explicit go/no-go threshold
- Team training on the new platform before the last wave, not after
Technologies used
Measured result
Every number below was measured and reported to the customer. Where we do not have a measured figure, the entry is a fact rather than a percentage — we would rather be precise than impressive.
- 4 waves, zero unplanned downtime
- 100% of waves had a rehearsed rollback
- 140 VMs migrated, all with rollback tested
- — licence cost reduction, modelled for the board
Order migration waves by blast radius, not by convenience. You want your first mistakes to be in the monitoring stack, not in the system that ships orders.