What is a Data Lake in AWS?

A Data Lake is a centralized repository that stores structured, semi-structured, and unstructured data at any scale — usually for analytics, ML, and search.

• Storage layer — Amazon S3 is the canonical Data Lake storage; cheap, durable, infinitely scalable.

• Catalog — AWS Glue Data Catalog stores schemas, partitions, and metadata.

• Ingestion — Kinesis Data Firehose, DMS, Glue, Snowball, partner ETL tools.

• Query / Analytics — Athena (serverless SQL), Redshift Spectrum, EMR (Spark/Hive), QuickSight.

• Governance — AWS Lake Formation manages permissions, row/column security, and audit.

Data Lake vs Data Warehouse: Lake holds raw data in any format (schema-on-read); Warehouse (Redshift) holds curated structured data (schema-on-write).