Azure Blob Storage
What it is
Blob Storage is Azure’s object store for unstructured data — files, images, videos, backups, logs, documents. Data is stored in containers as blobs, addressable over HTTP(S) via REST: <account>.blob.core.windows.net/<container>/<blob>.
Why it exists
Applications need cheap, massively scalable storage for binary/unstructured payloads that isn’t tied to a filesystem or a database schema. Blobs support trillions of objects and PB-scale, with tiered pricing.
Key ideas
- Hierarchy: storage account → container (like a folder/drive root) → blob.
- Blob types:
- Block blob — default; text/binaries; efficient for uploads (blocks can be uploaded in parallel).
- Append blob — optimized for append (logging) — only append is allowed.
- Page blob — random read/write, fixed 512-byte pages; backs unmanaged VM disks / VHDs.
- Access tiers (hot/cool/cold/archive) + lifecycle management automate cost.
- Features: snapshots, soft delete, versioning, immutability (immutable-storage), object replication (replicate blobs to another account), hierarchical namespace (for Data Lake Gen2).
- Concurrency: ETag / conditional headers for lease & overwrite safety.
How it fits (diagram)
Diagrams courtesy of Microsoft Learn / Azure docs: storage/blobs/storage-blobs-introduction
Exam notes
- Container = organizational unit for blobs — a single flat namespace + optional hierarchy.
- Know which blob type is for what: logs→append, VM disks→page, everything else→block.
- “Hot” is the default tier for new blobs.
- Azure Data Lake Storage Gen2 = blob storage with a hierarchical namespace.
Related
storage-account · access-tier · storage-performance · azure-tables · azure-queues · immutable-storage
📘 Source: Microsoft Learn — Blob Storage