Azure Blob Storage Versioning

Blob versioning is a feature of Azure Blob Storage that automatically manages, protects, and recovers data. It is designed to protect your data from accidental deletions or overwrites by maintaining earlier versions of a blob.

How Blob Versioning Works

When blob versioning is enabled for a storage account, Azure Blob Storage automatically creates a new version of a blob whenever the blob is modified or deleted. Each version is assigned a unique version ID.

Key Concepts:

• Current Version: The active version of the blob that is accessible by default.
• Previous Versions: Read-only snapshots of the blob at a specific point in time. These are retained according to your versioning policy.
• Versioning Policy: Configurable settings that determine how long previous versions are kept and whether to automatically delete older versions.

Enabling Blob Versioning

Blob versioning can be enabled at the storage account level. Once enabled, it applies to all blob types (Block, Append, and Page blobs) within that account. It's recommended to enable versioning when creating a new storage account or for existing accounts where data protection is critical.

To enable versioning:

1. Navigate to your storage account in the Azure portal.
2. Under the "Data protection" section, select "Versioning".
3. Toggle "Enable blob versioning" to "On".
4. Configure your retention policy for previous versions.
5. Click "Save".

Managing Blob Versions

You can manage blob versions using various tools:

• Azure Portal: Browse to a container, select a blob, and view its versions in the "Versions" tab. You can restore, download, or delete specific versions.
• Azure CLI: Use commands like az storage blob show with the --version-id parameter, or az storage blob copy to restore a specific version.
• Azure PowerShell: Similar cmdlets are available for managing blob versions.
• Azure SDKs: Programmatically access and manage blob versions using your preferred programming language.

Example: Restoring a Previous Version (Conceptual CLI)

# Assuming blob 'my-blob.txt' in container 'my-container' has version ID '0123456789ABCDEF'
# And you want to restore it to the current version

az storage blob copy --destination-blob my-blob.txt \
    --destination-container my-container \
    --source-blob my-blob.txt \
    --source-container my-container \
    --source-version-id 0123456789ABCDEF \
    --account-name my-storage-account \
    --account-key YOUR_ACCOUNT_KEY
        

Benefits of Blob Versioning

• Data Recovery: Easily recover from accidental deletions or modifications.
• Audit Trail: Provides a history of changes made to blobs.
• Simplified Management: Automatic version creation and management.
• Compliance: Helps meet data retention and compliance requirements.

Blob versioning is a powerful tool for ensuring the integrity and availability of your data in Azure Blob Storage.

Learn More on Azure Docs