Reviewed by Aditya Kumar · Last reviewed 2026-03-24
**Blob Storage**: Flat object namespace. No true directories—prefixes. Optimized for simple object storage. **ADLS Gen2**: Adds hierarchical namespace (filesystem semantics). True directories, atomic renames, POSIX-like ACLs. Built on Blob; supports both Blob and Data Lake APIs....
Blob Storage: Flat object namespace. No true directories—prefixes. Optimized for simple object storage. ADLS Gen2: Adds hierarchical namespace (filesystem semantics). True directories, atomic renames, POSIX-like ACLs. Built on Blob; supports both Blob and Data Lake APIs. Why Gen2: Data lake patterns need directory operations, ACLs, and analytics optimizations. Spark, Synapse, HDInsight use Gen2. Trade-off: Gen2 has slight overhead for small-object workloads; Blob is cheaper for pure object storage. Gen2 is required for Synapse Serverless SQL on ADLS. Cost: Similar; Gen2 adds hierarchical namespace fee. Best practice: Use Gen2 for data lakes; use Blob for simple object storage (backups, artifacts).
Pro-Move: 'We use Gen2 for our lake—ACLs and atomic renames enabled our Delta/Spark workflows; Blob for raw backup-only.' Red Flag: Using Blob for analytics when Gen2 is available—missing features.
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