Azure Blob Storage Concepts
This article explains the core concepts of Azure Blob Storage, a cloud object storage solution for modern cloud applications that can be accessed from anywhere in the world.
Azure Blob Storage is optimized for storing massive amounts of unstructured data, such as text or binary data. Unstructured data is data that doesn't adhere to a particular data model or definition, such as images, audio, video, audio, or any other type of binary data.
Key Concepts
Storage Account
A storage account provides a unique namespace in Azure for your data. Every object that you store in Azure Storage is organized under a storage account. A storage account has the following properties:
- Name: The storage account name must be unique across all of Azure.
- Region: The geographical location where your storage account is hosted.
- Replication: Determines how many copies of your data are maintained for durability and availability.
Containers
A container is a logical grouping of a set of blobs. You can think of a container as a directory in a file system. A storage account can contain an unlimited number of containers, and a container can contain an unlimited number of blobs.
Containers are created within a storage account. When you create a container, you specify a name that adheres to these naming conventions:
- Container names must be between 3 and 63 characters long.
- Container names can only contain lowercase letters, numbers, and hyphens.
- Container names must start and end with a letter or number.
- Container names must be formatted as valid DNS names.
Blobs
A blob is the simplest type of object storage. Any collection of binary data can be stored as a blob. Azure Blob Storage is suitable for storing:
- Images or documents for direct delivery to a browser.
- Files for distributed access.
- Data for backup, restore, disaster recovery, and data archiving.
- Data for analysis when running on-premises or hosted as a virtual machine in Azure.
- Streaming data for audio and video.
- Data for logging and auditing.
- Data for machine learning.
There are three types of blobs:
- Block blobs: Optimized for storing large amounts of unstructured data. Block blobs are made up of blocks of data that are uploaded independently and can be assembled as needed.
- Append blobs: Similar to block blobs, but optimized for append operations. They are made up of blocks, but you can only append data to the end of the blob.
- Page blobs: Optimized for random read/write operations. Page blobs are used to store virtual machine disk images.
Access Tiers
Azure Blob Storage offers different access tiers that can be used to store data at the lowest cost. The access tier you choose for a blob depends on how frequently you need to access it.
- Hot tier: Optimized for frequently accessed data. Low latency access, but higher storage costs.
- Cool tier: Optimized for infrequently accessed data. Higher latency, but lower storage costs.
- Archive tier: Optimized for rarely accessed data that can tolerate hours of retrieval time. Lowest storage costs, but highest retrieval costs and latency.
Note: Data in the cool or archive tiers can be moved to the hot tier if access frequency increases.
Data Redundancy
Azure Storage offers several options for data redundancy, ensuring your data is highly available and durable:
- Locally redundant storage (LRS): Provides at least 16 9s of durability by replicating your data synchronously three times within a single data center.
- Zone-redundant storage (ZRS): Provides at least 16 9s of durability by replicating your data synchronously across three Azure availability zones in the primary region.
- Geo-redundant storage (GRS): Provides at least 16 9s of durability by replicating your data synchronously three times within a single data center in the primary region, and asynchronously to a secondary region hundreds of miles away.
- Geo-zone-redundant storage (GZRS): Combines the high availability of ZRS with the disaster recovery capabilities of GRS.
Next Steps
Now that you understand the core concepts, you can explore how to get started with Azure Blob Storage: