🧠 Azure Blob Storage Smart Tier is GA

Azure Blob Storage Smart Tier has reached general availability. It is a zero-configuration approach to automatic storage cost optimisation: you enable it once, and Azure manages tier transitions for you based on actual access patterns. No lifecycle rules to author. No guessing at access frequency upfront.

What Smart Tier does

Smart Tier monitors blob access patterns and automatically moves objects between the hot, cool, and cold online access tiers. When data is not accessed for a period of time, it transitions to a cheaper tier. When data is accessed again, Azure immediately moves it back to hot.

The transition timeline works as follows:

• New blobs land in the hot tier.
• After 30 days of no access, a blob moves to the cool tier.
• After 60 more days (90 days total) of continued inactivity, it moves to the cold tier.
• Any access operation (Get Blob or Put Blob) resets the timer and immediately moves the object back to hot.

The archive tier is not part of smart tier. All objects stay on online tiers, which means retrieval is always instantaneous without a rehydration wait.

Why this matters over lifecycle management

Blob lifecycle management has been available for years and lets you write rules to tier or delete blobs based on last-modified time or last-access time. It is powerful, but requires you to predict access patterns upfront and maintain policies over time.

Smart Tier removes that burden:

• No rules to write or tune.
• No need to know access patterns before ingesting data.
• Transitions happen at the object level based on observed behaviour, not fixed schedules.
• Suitable for workloads with unpredictable or variable access patterns.

If you already know your data is cold after 90 days and will never be accessed again, lifecycle management with an archive transition is still a better fit. Smart Tier targets the uncertainty in between.

How the billing model works

Smart Tier uses the billing meters of the underlying capacity tier. There is no smart-tier-specific storage price. Objects are billed at hot rates when in the hot tier, cool rates when in the cool tier, and so on.

The only smart-tier-specific charge is a small monthly monitoring fee:

• $0.04 per 10,000 objects (over 128 KiB) managed by smart tier each month.
• Objects 128 KiB or smaller are not charged a monitoring fee. They stay on the hot tier permanently (labelled SmartHot-small) because moving small objects to cooler tiers would not produce meaningful savings and would trigger the minimum billable object size charge on cool and cold tiers.

Additional billing rules to be aware of:

The absence of early deletion penalties and data retrieval charges is significant. With manually managed cool and cold tiers, accessing data unexpectedly could lead to retrieval charges. Smart Tier absorbs those costs and prices all access at hot tier transaction rates.

Prerequisites

Smart Tier requires:

• A Standard general-purpose v2 (GPv2) storage account. Legacy GPv1 and premium accounts are not supported.
• Zone-redundant storage: ZRS, GZRS, or RA-GZRS. LRS and GRS accounts are not eligible.
• Block blobs only. Page blobs and append blobs are not supported.

The ZRS requirement is worth noting if you currently use LRS for cost reasons. Enabling smart tier is not possible without converting to a zone-redundant configuration first.

Enabling Smart Tier

Smart Tier is configured by setting the default account access tier to Smart on a supported storage account.

At account creation time (Azure portal)

1. Navigate to Storage accounts and select Create.
2. Complete the Basics tab.
3. On the Advanced tab, under Blob storage, set Access tier to Smart.
4. Select Review + Create.

On an existing account (Azure portal)

1. Navigate to your storage account.
2. Under Settings, select Configuration.
3. Locate Blob access tier (default) and select Smart.
4. Save your changes.

When you enable smart tier on an existing account, all blobs that do not have an explicitly set access tier migrate to smart tier. Blobs with an explicit tier set are not affected.

Using Azure CLI

# Create a new account with smart tier as default
az storage account create \
  --name mystorageaccount \
  --resource-group myresourcegroup \
  --location eastus \
  --sku Standard_ZRS \
  --kind StorageV2 \
  --min-tls-version TLS1_2 \
  --access-tier Smart

# Update an existing account to smart tier
az storage account update \
  --name mystorageaccount \
  --resource-group myresourcegroup \
  --access-tier Smart

Using Azure PowerShell

# Create a new account with smart tier as default
New-AzStorageAccount `
  -ResourceGroupName "myresourcegroup" `
  -Name "mystorageaccount" `
  -Location "eastus" `
  -SkuName "Standard_ZRS" `
  -Kind "StorageV2" `
  -AccessTier "Smart"

# Update an existing account to smart tier
Set-AzStorageAccount `
  -ResourceGroupName "myresourcegroup" `
  -Name "mystorageaccount" `
  -AccessTier "Smart"

Monitoring Smart Tier distribution

Azure Monitor exposes built-in metrics for smart tier at no additional cost. To see how blobs are distributed across tiers:

1. Open your storage account in the Azure portal.
2. Select Monitoring > Metrics.
3. Configure the metric as follows:
   • Metric Namespace: Blob
   • Metric: Blob Count or Blob Capacity
   • Aggregation: Avg
   • Apply splitting: split by Blob tier and Blob type

The following blob tier values are specific to smart tier:

Key constraints and considerations

Before enabling smart tier across all accounts, review these constraints:

• No archive tier support. Smart Tier only manages hot, cool, and cold tiers. If you need archive for compliance or long-term retention, combine smart tier with lifecycle management delete rules.
• Moving blobs out of smart tier is one-way. Once you explicitly set a tier on a blob, it leaves smart tier management and cannot be automatically moved back.
• Lifecycle management tiering rules do not apply to smart-tier-managed objects. However, lifecycle management delete rules still work on smart tier objects.
• Redundancy conversion to LRS or GRS is not supported while smart tier is active.
• GZRS failover. If a GZRS account fails over, you have 60 days to convert the resulting LRS account back to zone-redundant storage to restore smart tier eligibility.
• REST API version 2025-08-01 or later is required for full smart tier support.
• Get Blob Properties, Get Blob Metadata, and Get Blob Tags are not considered access operations. Only Get Blob and Put Blob reset the tier transition timer.

Regional availability

Smart Tier is generally available in nearly all public Azure regions with zonal redundancy. Three regions remain in public preview:

• Israel Central
• Qatar Central
• UAE North

Azure Government and Azure operated by 21Vianet (China) are also in public preview. To enable smart tier in those regions, register the Smart Tier (account level) preview feature via the Azure portal preview features blade.

When to use Smart Tier versus alternatives

Summary

Smart Tier removes the operational overhead of managing blob tier transitions manually. You pay for the underlying capacity tier your data actually resides in, plus a small monthly monitoring fee for eligible objects. No early deletion penalties, no retrieval charges, and no rules to maintain.

For workloads where access patterns are hard to predict, or where you want to reduce FinOps complexity without sacrificing performance, Smart Tier is a practical default to consider enabling on new GPv2 storage accounts today.

References

• Optimise Azure Blob Storage costs with smart tier
• Access tiers for blob data
• Azure Blob Storage pricing
• Best practices for using blob access tiers
• Optimise costs by automatically managing the data lifecycle