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Managing and storing vast amounts of data such as such as images, videos, log files, documents, etc securely and efficiently is crucial for businesses of all sizes. Traditional on-premises storage solutions often struggle to keep pace with these demands, leading many businesses to turn to cloud-based storage solutions for scalability, reliability, and cost-effectiveness.

Azure Blob Storage, a part of Microsoft’s Azure cloud computing platform, offers a scalable, cost-effective solution for storing and managing unstructured data in the cloud. It offers a scalable, secure, and flexible storage environment specifically designed to handle unstructured data, such as documents, images, videos, and more.

What is Azure Blob Storage?

Azure Blob Storage is Microsoft’s cloud-based object storage service, purpose-built for storing and managing large amounts of unstructured data. Leveraging the power of the cloud, Azure Blob Storage provides businesses with a reliable and scalable solution to store diverse data types, ranging from text files to multimedia content. By abstracting away the complexities of storage infrastructure management, Azure Blob Storage enables organizations to focus on deriving insights and value from their data, rather than worrying about storage capacity or performance limitations.

Azure blob storage
Source: Microsoft Learn

At its core, Azure Blob Storage organizes data into containers, which serve as logical units for grouping related blobs (objects). Within each container, blobs can be stored in various formats, including block blobs, append blobs, and page blobs, each optimized for different use cases.

  • Block Blobs: Ideal for storing large media files like videos and archives. Block blobs are uploaded in smaller chunks, enabling efficient management of voluminous data.
  • Append Blobs: Optimized for scenarios involving data appendage, such as log files where new information is continuously added without modifying existing content.
  • Page Blobs: Designed for random access to specific data segments, making them well-suited for virtual hard disks (VHDs) that require granular control.

Through simple REST-based APIs or client libraries provided by Microsoft, users can interact with Azure Blob Storage to upload, download, and manipulate data seamlessly, irrespective of geographic location or underlying infrastructure.

Beyond basic file storage, Azure Blob Storage is a powerful tool that integrates with CDN networks for smooth media delivery, safeguards data with backup and disaster recovery features, and serves as the foundation for data lakes and analytics. Machine learning models can leverage Blob Storage for training data, and IoT devices can utilize it to store and process data efficiently.

Azure Blob storage tiers

Azure Blob Storage offers a tiered storage system, allowing you to store your data in the most cost-effective and performance-oriented manner. These tiers cater to varying data access needs, providing a balance between affordability and retrieval speed. Azure Blob Storage offers two main categories: online and archive. The online tiers are designed for data that you expect to access frequently or on short notice. They provide faster retrieval times compared to the archive tier, making them suitable for data you need to access readily.

Online Tier

There are three online access tiers within Azure Blob Storage:

1. Hot Tier:

The Hot Access Tier is optimized for frequently accessed data and offers low-latency access to stored blobs. Data stored in the Hot Access Tier is immediately accessible and is ideal for workloads that require frequent read and write operations. While the Hot Access Tier offers the highest performance, it also tends to have higher storage costs compared to other tiers.

2. Cool Tier:

The Cool Access Tier is designed for data that is accessed less frequently but still requires quick access when needed. Data in the cool tier should be stored for a minimum of 30 days. Data stored in the Cool Access Tier incurs lower storage costs compared to the Hot Access Tier but may have slightly higher access costs. This tier is suitable for data with occasional access patterns, such as backups, archives, or infrequently accessed business data.

3. Cold Tier

The Cold tier is an online storage tier designed to efficiently store data that experiences infrequent access or updates while still necessitating prompt retrieval when required. Data stored in the Cold tier is mandated to remain for a minimum duration of 90 days. This tier offers reduced storage expenses compared to the Cool tier but incurs higher access costs.

Archival Tier

The Archive tier is an offline storage tier engineered for the storage of rarely accessed data with flexible latency needs, typically spanning several hours. Data allocated to the archive tier must be retained for a minimum of 180 days. This tier offers the lowest storage costs and is suitable for data with minimal retrieval demands.

You cannot read or modify data in the Archive tier. To access or download a blob stored in the archive tier, it must first undergo rehydration to an online tier—be it hot, cool, or cold. The process of rehydrating data from the archive tier can take up to 15 hours, depending upon the priority assigned to the rehydration operation.

Azure Blob Storage Types

Azure Blob Storage caters to diverse data storage needs by offering two primary storage account types: Standard (GPv2) storage and Premium storage.

Standard (GPv2) storage is the recommended choice for most scenarios. It excels at cost-effectively storing large volumes of unstructured data, making it ideal for static websites, media libraries, backups, and archives. You can choose between the hot, cool, and archive tiers to optimize cost and access speed based on your data’s access frequency.

Premium storage caters to demanding workloads requiring ultra-low latency access and exceptional performance. It’s ideal for scenarios involving real-time analytics, high-performance computing, and mission-critical applications

Azure Blob Storage Pricing

Azure Blob Storage pricing adheres to a pay-as-you-go model, meaning you are charged only for the resources you utilize. The total cost encompasses several factors such as data storage, data transfer, read/write operations, etc.

Data storage prices

Data storage prices are based on the pay-as-you-go model. All prices are calculated for per GB per month, and the cost varies based on the different tiers where they are stored.

azure blob data storage pricing
Source: Microsoft Azure

Azure Storage Reserved Capacity

Azure Storage Reserved Capacity offers cost savings by committing to one or three years of Azure Storage. It’s available in increments of 100 TB and 1 PB, with pricing calculated per month.

azure blob storage pricing, azure storage reserved capacity
Source: Microsoft Azure

Cool, Cold, and Archive early deletion

Blobs transitioned to the Archive, Cool, or Cold tiers incur early deletion periods of 180 days, 30 days, and 90 days, respectively, in addition to the per-GB, per-month charge. This charge is prorated based on the duration of storage in the respective tier. For instance, if a blob moved to the Archive tier is subsequently deleted or transitioned to the Hot tier after 45 days, the customer is billed for 135 days (180 minus 45) of storage in the Archive tier.

Operations and data transfer

Beyond data storage costs, Azure Blob Storage charges for operations performed on your data and for data transfers. Reads (downloads) are generally cheaper than writes (uploads), and minimizing unnecessary operations can help control costs. Data transfer charges apply to both uploading and downloading data, with costs influenced by data volume and transfer region.

azure blob storage pricing, azure blob data transfer cost, azure blob data operation cost
Source: Microsoft Azure

SSH File Transfer Protocol (SFTP)

Azure Blob storage supports the SSH File Transfer Protocol (SFTP) which provides the ability to securely connect to Blob Storage accounts via an SFTP endpoint. This allows you to leverage SFTP for file access, file transfer, file management, etc.

azure blob storage SSH file transfer pricing
Source: Microsoft Azure

Blob Index

The Blob Index is a sophisticated data sub-resource for blobs, comprising user-defined key/value tag attributes that are automatically indexed for querying purposes. This feature facilitates a managed multi-dimensional classification for blob objects, thereby enabling swift, straightforward, and cost-effective data discovery capabilities that extend beyond mere listing via prefix filters on blob names. The pricing details for different storage tiers are as follows

azure blob index pricing
Source: Microsoft Azure

Data transfer prices for block blobs

When data is written to a GRS, RA-GRS, GZRS, or RA-GZRS account, it undergoes replication to another Azure region. The geo-replication data transfer charge pertains to the bandwidth utilized in replicating data to the secondary Azure region. This charge is applicable even when altering the storage account’s replication setting from LRS to GRS or RA-GRS, or from ZRS to GZRS or RA-GZRS.

azure blob storage pricing, block blob pricing
Source: Microsoft Azure

Blob inventory

Blob inventory furnishes a comprehensive inventory of containers, blobs, blob versions, and snapshots within your storage account, including their respective properties. This tool generates a report in either CSV or Apache Parquet format, with frequency options of daily or weekly. The report serves multiple purposes, including auditing retention, legal hold, or encryption status. Moreover, it can be seamlessly integrated into workflows as a scheduled alternative to the List Blobs API.

azure blob storage pricing for blob inventory
Source: Microsoft Azure

Other features

Other features of Azure blob storage include Change feed and Encryption scopes. Their scope and pricing are listed below.

Change feed furnishes a systematic log of alterations in Blob data. Initially deactivated, this feature can be activated at the Storage account level. Upon activation, the Change feed meticulously monitors each alteration to Blobs and archives the corresponding change event

azure blob storage pricing for blob chnages
Source: Microsoft Azure

Encryption scopes grant the flexibility to manage encryption either at the container level or for individual blobs. This can be achieved using either a customer-managed key stored in Key Vault or a Microsoft-managed key.

azure blob storage pricing for encryption scopes
Source: Microsoft Azure


Azure Blob Storage is a versatile and reliable solution for storing and managing unstructured data in the cloud. With its scalability, durability, security features, and flexible pricing options, it empowers organizations to build and deploy data-driven applications with confidence. By understanding its features, functionality, and pricing details, businesses can efficiently utilize Azure Blob Storage to meet their storage needs and optimize their cloud storage costs effectively.

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