# Cutover runbook outline

The sections every cutover runbook needs. Fill each one in for your migration, and rehearse it before the day.

From Bit Movers, bitmovers.co.uk. Free to use and adapt.


## 1. Summary

- What is moving, from which systems to which.
- The date and the freeze window, with the rehearsal timings it was sized from.
- Who makes the go or no-go call, and who they can reach on the night.


## 2. People

For every step: the owner, a backup, and how to reach them during the window.

| Role | Name | Backup | Contact |
| --- | --- | --- | --- |
| Cutover lead | | | |
| Migration engineer | | | |
| Source system owner | | | |
| Target system owner | | | |
| Business sign-off | | | |


## 3. Before the day

- [ ] Last rehearsal reconciled cleanly, and its timings are recorded.
- [ ] Users told when the old system goes read-only and when the new one opens.
- [ ] Integrations, scheduled jobs and email notifications that write to either system are listed, with how each is paused.
- [ ] Backups of the target taken, and the restore tested.
- [ ] Access for everyone on the night confirmed in advance.


## 4. The window

Each step with a planned start time, expected duration and the person doing it. Record the actual time as you go.

1. Freeze the source: read-only, integrations paused, final users logged out.
2. Final extract, or the delta since the last rehearsal.
3. Transform and validate. Stop if validation fails.
4. Load into the target.
5. Reconcile: counts, totals, integrity, spot checks.
6. Go or no-go decision, against criteria written down before the day.


## 5. Go or no-go criteria

- Every object reconciles: source = loaded + held back.
- Financial totals match to the penny.
- Key users have checked their own records in the new system.
- Anything else that would stop you: write it here before the day, not on the night.


## 6. Rollback

- The point after which rolling back is no longer simple, and what happens after it.
- How the source is reopened, and integrations restarted against it.
- How partial loads in the target are removed or isolated.
- Who tells users, and what they are told.


## 7. After go-live

- [ ] Integrations restarted against the new system, and their first runs checked.
- [ ] The old system kept read-only, not switched off, until the agreed date.
- [ ] A daily check-in for the first week, with a named person for data questions.
- [ ] Working copies of migration data deleted at the end, and the deletion confirmed in writing.