Azure Blob Storage – Overview

Azure Blob Storage is a cloud service for storing unstructured data as objects called blobs. It can store any type of text or binary data, such as documents, images, videos, and application installers. Blob Storage is also known as object storage.

Common Use Cases

• Serving images or documents directly to a browser

• Storing files for distributed access (e.g., installers)

• Streaming video and audio

• Backup, restore, disaster recovery, and archiving

• Storing data for analysis by on-premises or Azure-hosted services

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Blob Service Resources

Blob Storage is organized into three resource levels:

1. Storage Account – The top-level container for all Azure Storage services

2. Containers – Logical groupings of blobs within a storage account

3. Blobs – Individual data objects stored in containers

✔️ A storage account can contain unlimited containers, and each container can store unlimited blobs.

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Blob Containers

A container groups a set of blobs. Every blob must belong to a container.

Container Properties

• Name

  • Lowercase letters, numbers, and hyphens only

  • Must start with a letter or number

  • Length: 3–63 characters

• Public Access Level

  • Private – No anonymous access (default)

  • Blob – Anonymous read access to blobs only

  • Container – Anonymous read and list access to the entire container

✔️ Containers can be created using:

• Azure Portal

• PowerShell (New-AzStorageContainer)

✔️ Plan container organization carefully for security and management.

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Blob Access Tiers

Azure Blob Storage offers access tiers optimized for different usage patterns:

Hot Tier

• Optimized for frequent access

• Lowest access cost

• Higher storage cost

• Default tier for new storage accounts

Cool Tier

• Optimized for infrequent access

• Data must be stored for at least 30 days

• Lower storage cost, higher access cost than Hot

Archive Tier

• Optimized for rarely accessed data

• Retrieval latency of several hours

• Data must remain for at least 180 days

• Lowest storage cost, highest access cost

✔️ You can switch between tiers at any time based on usage needs.

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Blob Lifecycle Management

Blob lifecycle management provides rule-based automation to manage data over time (available for GPv2 and Blob storage accounts).

Capabilities

• Automatically move blobs:

  • Hot → Cool

  • Hot → Archive

  • Cool → Archive

• Delete blobs when they expire

• Run rules once per day

• Apply rules to:

  • Entire containers

  • Specific blobs using prefixes

Example Scenario

• Frequently accessed data → Hot

• Occasionally accessed after 2 weeks → Cool

• Rarely accessed after 1 month → Archive

✔️ Lifecycle policies help minimize storage costs while maintaining performance.

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Blob Types

Azure Storage supports three types of blobs:

Block Blobs (Default)

• Made of blocks of data

• Ideal for text and binary data

• Commonly used for files, images, and videos

Append Blobs

• Optimized for append operations

• Ideal for logging scenarios

Page Blobs

• Up to 8 TB in size

• Optimized for frequent read/write operations

• Used by Azure VMs for OS and data disks

✔️ Once created, a blob’s type cannot be changed.

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Blob Upload Tools

Multiple tools are available to upload data to Blob Storage:

• AzCopy – Command-line tool for copying data across storage accounts and containers

• Azure Storage Data Movement Library – .NET library used by AzCopy

• Azure Data Factory – Supports secure data transfer using various authentication methods

• Blobfuse – Virtual file system driver for accessing blobs via Linux file systems

• Azure Data Box Disk – Physical SSDs for large on-premises data transfers

• Azure Import/Export Service – Import/export large datasets using customer-provided drives

• Azure Storage Explorer – GUI tool for managing and uploading data