Long-term, cost-optimized storage for data that is rarely accessed but must be retained — typically for compliance, legal, or historical purposes. Archival storage tiers offer the lowest cost per GB but have slower retrieval times (minutes to hours). Key services: AWS S3 Glacier / Glacier Deep Archive, Azure Archive Storage, GCP Archive Storage, OCI Archive Storage.
A healthcare provider retains patient records for 10 years to meet regulatory requirements. They move records older than 90 days to AWS S3 Glacier using lifecycle policies, reducing storage costs by 80% compared to standard S3 while still meeting compliance obligations.