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Azure Blob Storage — Trivia & Quick Facts

Terse, quiz-worthy facts about Azure Blob Storage — specific numbers, limits, and defaults worth memorizing.

  1. Storage account names are globally unique, 3-24 characters, lowercase letters and digits only.
  2. A general-purpose v2 (StorageV2) account is the normal default for most Blob workloads.
  3. Blob types are block, append, and page blobs.
  4. Standard online tiers are Hot, Cool, and Cold; Archive is offline.
  5. GPv2 minimum-duration charging is generally 30 days for Cool, 90 for Cold, and 180 for Archive.
  6. Archive rehydration can take up to 15 hours at standard priority.
  7. Redundancy is selected at the storage-account level and is shared by every service in that account.
  8. GRS/GZRS replication to the secondary region is asynchronous — it is not a zero-data-loss guarantee.
  9. Azure RBAC Contributor does not inherently grant Blob data access — a separate data-plane role is required.
  10. Microsoft recommends Entra ID authorization and disabling Shared Key where dependencies permit.
  11. SAS tokens can be used without exposing the account key, but overly broad/long-lived SAS is still a bearer credential risk.
  12. Hierarchical namespace enables real directories and ACLs and cannot be reverted to flat namespace once enabled.
  13. Lifecycle management can tier or delete supported blobs but cannot rehydrate archived blobs.
  14. Blob soft delete and versioning both preserve billable data copies.
  15. Without HNS, blob-name slashes represent virtual folders, not atomic directories — "renaming" one can mean copying and deleting many objects.