Access Tiers in Azure Blob Storage
Azure Blob Storage offers different access tiers to optimize costs by storing infrequently accessed data in a more cost-effective tier.
Understanding Access Tiers
Blob storage offers the following access tiers:
- Hot tier: Optimized for frequently accessed data. This tier has the highest storage costs but the lowest access costs.
- Cool tier: Optimized for infrequently accessed data. This tier has lower storage costs and higher access costs compared to the hot tier.
- Archive tier: Optimized for rarely accessed data. This tier has the lowest storage costs but the highest access costs, and data retrieval can take several hours.
Choosing the Right Tier
The best tier for your data depends on how frequently you access it. Consider the following factors:
- Access frequency: How often will data be read or written?
- Data retention: How long will the data be stored?
- Cost: Storage costs versus access and transaction costs.
Managing Access Tiers
You can set the access tier for a blob or a container. For blobs, you can rehydrate data from cool or archive tiers to the hot tier if needed.
Setting Access Tier for a Blob
You can set the access tier for an individual blob during upload or by updating an existing blob.
Note
Rehydrating data from the archive tier to the hot or cool tier can take several hours and incurs costs.
Setting Access Tier for a Container
You can set a default access tier for all blobs within a container. New blobs uploaded to the container will inherit this tier unless specified otherwise.
Access Tier Pricing
Each access tier has different pricing models:
| Tier | Storage Cost | Access Cost | Transaction Cost | Retrieval Cost |
|---|---|---|---|---|
| Hot | Highest | Lowest | Lowest | N/A |
| Cool | Medium | Medium | Medium | Low |
| Archive | Lowest | Highest | Highest | High (per GB) |
For detailed pricing information, please refer to the Azure Blob Storage pricing page.
When to Use Each Tier
- Hot: Active data, frequently accessed applications, temporary files.
- Cool: Backups, disaster recovery files, infrequently accessed operational data.
- Archive: Long-term archival, compliance data, data that is rarely accessed but must be retained.
Tip
Consider using lifecycle management policies to automatically move blobs between tiers based on age or last accessed date, further optimizing costs.
Example: Setting Access Tier using Azure CLI
az storage blob update-tier --account-name --container-name --name --tier Cool
Example: Setting Default Access Tier for a Container using Azure CLI
az storage container update --account-name --name --default-encryption-scope --default-tier Cool