Phase 7.1 — Quiesce the estate

Everything stops before anything is touched.

Every virtual machine is shut down, automatic start-up is disabled so nothing comes back by surprise in the middle of an operation, stale disk snapshots going back to 2023 are consolidated, and a full cold backup is taken.

Doing the hardware work on powered-down machines makes every step that follows both safer and faster — and it is why this phase comes first rather than the preparation work.

Downtime: both clusters, from here on for the duration of the migration.