In shortInventory first / Move in waves / Verify everything / The surprising bit.
1. Inventory first
We found 11 petabytes of data we thought were 4. The other 7 were backups of backups, and one very confusing folder named "misc".
2. Move in waves
We started with cold data, moved to warm, and finished with hot. Each wave taught us something for the next.
3. Verify everything
Checksums on every object. If a hash did not match, we copied it again. We found 412 mismatches, all of them harmless.
4. The surprising bit
The move paid for itself in four months, and we discovered a fridge-sized server in the corner that nobody knew about.
Written by Maurice Wingate, Chief Security Rooster. Disagree? Tell us. We read every message, usually before the second coffee.