New Azure storage account type

In Azure, there previously has been only one kind of storage account, which is now called a “General Purpose” storage account.  Just introduced is a new kind of storage account, called “Cool Blob Storage”.  When creating a storage account, the “Account kind” will now list two options: the existing type “General purpose” as well as the new type “Blob storage”.

“General Purpose” storage accounts provide storage for blobs, files, tables, queues and Azure virtual machine disks under a single account.  “Cool Blob Storage” storage accounts are specialized for storing blob data and support choosing an access tier, which allows you to specify how frequently data in the account is accessed.  Choose an access tier that matches your storage needs and optimizes costs.

The access tiers available for blob storage accounts are “hot” and “cold”.  In general, hot data is classified as data that is accessed very frequently and needs to be highly durable and available.  On the other hand, cool data is data that is infrequently accessed and long-lived.  Cool data can tolerate a slightly lower availability, but still requires high durability and similar time to access and throughput characteristics as hot data.  For cool data, slightly lower availability SLA and higher access costs are acceptable tradeoffs for much lower storage costs.  Azure Blob storage now addresses this need for differentiated storage tiers for data with different access patterns and pricing model.  So you can now choose between Cool and Hot access tiers to store your less frequently accessed cool data at a lower storage cost, and store more frequently accessed hot data at a lower access cost.  The Access Tier attribute of hot or cold is set at an account level and applies to all objects in that account.  So if you want to have both a hot access tier and a cold access tier, you will need two accounts.  If there is a change in the usage pattern of your data, you can also switch between these access tiers at any time.

Hot access tier
Cool access tier
(RA-GRS reads)
Usage charges
Higher storage costs
Lower access and transaction costs
Lower storage costs
Higher access and transaction costs
Minimum object size
Minimum storage duration
(Time to first byte)
Performance and Scalability
Same as general purpose storage accounts

Some common scenarios with the Cool tier include: backup data, disaster recovery, media content, social media photos and videos, scientific data, and so on.


Going forward, Blob storage accounts are the recommended way for storing blobs, as future capabilities such as hierarchical storage and tiering will be introduced based on this account type.  Note that Blob storage accounts do not yet support page blobs or Zone-redundant storage (ZRS).

More info:

Introducing Azure Cool Blob Storage

Azure Blob Storage: Cool and Hot tiers

About Azure storage accounts

Microsoft launches ‘cool blob’ Azure storage – at 1¢ per GB monthly

Microsoft Unveils Cheaper Azure Cool Blob Storage Option

About James Serra

James is a big data and data warehousing solution architect at Microsoft. Previously he was an independent consultant working as a Data Warehouse/Business Intelligence architect and developer. He is a prior SQL Server MVP with over 25 years of IT experience.
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4 Responses to New Azure storage account type

  1. Pingback: Cool Storage – Curated SQL

  2. Steve says:

    Useful James, thanks.

    One question we are often asked regarding cool blob storage is the access / retrieval time. i.e. Does it take longer to extract data from Cool Blob Store than the equivalent Hot (I understand there is a penalty charge with cold)?

    Consider a situation where you have a HDInsight Cluster sitting over Hot storage for ah-hoc analysis with swathes of data archived in Cold Storage. What if you want to perform some (rare/adhoc) analysis on a data set that resides in Cold Storage?

    Assuming you have to first move/copy it into Hot storage, perform the analysis and move it back/delete. 1) Is this the correct approach and 2) what’s the retrieval time from Cold to Hot? (Compared with moving from Hot to Hot as I realise it will be size dependent)

    • James Serra says:

      Hi Steve,

      The retrieval time with cool blob storage is the same as hot storage. The only difference is the SLA (99.9% to 99%). So no need to move the cold storage to hot for performance reasons.

  3. Pingback: Azure Storage pricing | James Serra's Blog