LEARN. PRACTICE. GROW.Concept and mechanism
DMS full-load completion does not by itself establish that every record was compared and reconciled. Inspect validation states, pending records, mismatches, and limitations of the selected path. Validation adds queries and consumption to databases and networking; it needs time and capacity in the plan. While the source continues receiving changes, distinguish copying progress, replication, and data checks. Cutover should have criteria defined with business owners. A connectivity indicator or low lag does not replace an explicit reconciliation requirement.
Guided application
After the target accepts writes, returning DNS to the source may lose visibility of new transactions. Prepare preservation, reconciliation, and return decisions in advance. This does not mean every rollback requires restoration: with a shared database and proven compatibility, application rollback may be valid. In cross-engine migration, copying tables does not automatically convert types, procedures, and engine-specific behavior. Validate business flows. For RUN handover, confirm access, alerts, escalation, runbooks, and rehearsals with APS. Finally, a monthly CFT interface discovered before retirement needs an owner and exit condition, with visible coexistence cost and a validated alternative.
The VM is in the cloud, but the night shift cannot access diagnostics. Technical migration finished; operational transition did not.
Common pitfalls
Full load as equality; DNS as reconciliation; copied procedure as compatibility; RUN as automatic recipient of unresolved work.
Related topics: Organization, identity, and controls · Hybrid networking, DNS, and segmentation
Accept data and service through evidence and close dependencies before declaring retirement complete.
Reference: AWS DMS data validation · SAP-C02