---
source: https://iinventedlight.com/library/notes/azure-blob-storage.md
title: "Azure Blob Storage and its access tiers"
license: CC-BY-4.0
license_url: https://creativecommons.org/licenses/by/4.0/
source_license: "CC BY 4.0 (MicrosoftDocs/azure-docs); prose restates or closely paraphrases cited source lines"
license_family: azure-docs-ccby
rule_check: "needs rule check (family not in auto-publish rule; check.mjs auto-approves only usgov and arxiv-ccby)"
attribution: "Summary by iinventedlight (AI-assisted). Sources: Microsoft Learn (Azure docs), Introduction to Blob (object) Storage - Azure Storage, CC BY 4.0 (MicrosoftDocs/azure-docs); Microsoft Learn (Azure docs), Access tiers for blob data - Azure Storage, CC BY 4.0 (MicrosoftDocs/azure-docs)."
author: "iinventedlight (synthesis of cited sources); text drafted with AI assistance"
date: 2026-11-04
status: published
checked_on: 2026-11-04
as_of: 2026-11-04
confidence: medium
untested: "No code was run for this note; only the fetched documentation pages were read."
category: coding-references
topic_area: "code-ai-eng: Azure"
tags: ['azure', 'blob-storage', 'object-storage']
sources:
  - id: S1
    title: "Introduction to Blob (object) Storage - Azure Storage"
    publisher: Microsoft Learn (Azure docs)
    url: https://learn.microsoft.com/en-us/azure/storage/blobs/storage-blobs-introduction
    accessed: 2026-11-04
    license: "CC BY 4.0 (MicrosoftDocs/azure-docs)"
  - id: S2
    title: "Access tiers for blob data - Azure Storage"
    publisher: Microsoft Learn (Azure docs)
    url: https://learn.microsoft.com/en-us/azure/storage/blobs/access-tiers-overview
    accessed: 2026-11-04
    license: "CC BY 4.0 (MicrosoftDocs/azure-docs)"
---
# Azure Blob Storage and its access tiers

**Answer:** Azure Blob Storage is Microsoft's object storage solution for the cloud. Blob Storage is optimized for storing massive amounts of unstructured data, which is data that doesn't adhere to a particular data model or definition, such as text or binary data. (S1)

## Access

- Users or client applications can access objects in Blob Storage via HTTP or HTTPS from anywhere in the world. (S1)
- You can access objects through the Azure Storage REST API, Azure PowerShell, Azure CLI, or an Azure Storage client library. (S1)
- A storage account provides a unique namespace in Azure for your data. (S1)
- Every object that you store in Azure Storage has an address that includes your unique account name. (S1)

## Access tiers

- Azure storage offers different access tiers so that you can store your blob data in the most cost-effective manner based on how it's being used. (S2)
- Hot tier: an online tier optimized for storing data that is accessed or modified frequently. (S2)
- Cool tier: an online tier optimized for storing data that is infrequently accessed or modified; data should be stored for a minimum of 30 days. (S2)
- Cold tier: an online tier for data that is rarely accessed or modified, but still requires fast retrieval; data should be stored for a minimum of 90 days. (S2)
- Archive tier: an offline tier for data that is rarely accessed and has flexible latency requirements, on the order of hours; data should be stored for a minimum of 180 days. (S2)

## Claims
- id: C1
  claim: Blob Storage is Microsoft's cloud object storage.
  source: S1
  evidence: "Azure Blob Storage is Microsoft's object storage solution for the cloud."
- id: C2
  claim: A storage account provides a unique namespace.
  source: S1
  evidence: "A storage account provides a unique namespace in Azure for your data."
- id: C3
  claim: Cool-tier data should be stored at least 30 days.
  source: S2
  evidence: "Data in the cool tier should be stored for a minimum of 30 days."
- id: C4
  claim: Archive-tier data should be stored at least 180 days.
  source: S2
  evidence: "Data in the archive tier should be stored for a minimum of 180 days."

## Sources
- [S1] Introduction to Blob (object) Storage - Azure Storage. Microsoft Learn (Azure docs). https://learn.microsoft.com/en-us/azure/storage/blobs/storage-blobs-introduction . License: CC BY 4.0 (MicrosoftDocs/azure-docs). Accessed 2026-11-04.
- [S2] Access tiers for blob data - Azure Storage. Microsoft Learn (Azure docs). https://learn.microsoft.com/en-us/azure/storage/blobs/access-tiers-overview . License: CC BY 4.0 (MicrosoftDocs/azure-docs). Accessed 2026-11-04.

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted).