Cloud migrations rarely fail because the technology does not work. They fail because something was missed: a dependency, a licence restriction, a DNS record or a test that nobody ran. This checklist sets out the questions worth answering before, during and after a move.

Before the migration

  • Inventory everything. List servers, applications, databases, scheduled jobs, file shares and integrations.
  • Map dependencies. Record which systems talk to which, over which ports and protocols.
  • Classify workloads. Rank each by business criticality and technical complexity.
  • Choose a strategy per workload. Rehost, replatform, refactor, replace, retain or retire.
  • Check licensing. Some software licences restrict how and where it can run.
  • Estimate costs. Include compute, storage, data transfer, backup and support.
  • Prepare the landing zone. Identity, networking, security baselines and logging should exist before workloads arrive.

During the migration

  • Take verified backups. Confirm they can be restored, not just that they completed.
  • Plan data transfer. Large datasets may need incremental synchronization before final cutover.
  • Lower DNS TTLs in advance. This lets traffic switch faster when records change.
  • Define acceptance tests. Agree who tests what, and what counts as success.
  • Write a rollback plan. Decide in advance when you will roll back and how.
  • Communicate. Tell users when changes will happen and whom to contact.

After the migration

  • Verify data integrity. Compare record counts and checksums where practical.
  • Review access. Remove temporary permissions granted for the migration.
  • Monitor closely. Watch performance, errors and costs during the first weeks.
  • Decommission carefully. Keep old systems available for an agreed period before removal.
  • Document the result. Update diagrams, runbooks and recovery procedures.

Set expectations honestly

Duration, downtime and savings depend on the complexity of each workload. Treat any generic estimate with caution until discovery is complete. For help planning your own move, see our cloud migration and modernization service.