Blob Storage tiers - immutable storage

Question

Blob Storage tiers - immutable storage

Chris Heys 5

https://learn.microsoft.com/en-gb/training/modules/design-data-storage-solution-for-non-relational-data/5-design-for-azure-blob-storage

This Microsoft Learn article includes two mentions of "Hot, Cool, and Archive access tiers" with regards to immutable storage. Please can this be updated to include the Cold tier?

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Answer 1

Vallepu Venkateswarlu 10,590 Microsoft External Staff Moderator

Hi Chris Heys,

Welcome to Microsoft Q&A Platform

Azure Blob immutable storage supports four online tiers (Hot, Cool, Cold) plus Archive, but that Learn module currently only calls out Hot, Cool, and Archive.

The Cold tier (online, infrequently accessed data with a 90-day minimum retention) is fully supported for container-level and version-level WORM policies just like the other tiers. I’ve logged a request to update the article to read:

“Immutable Blob Storage supports Hot, Cool, Cold, and Archive access tiers.”

Reference:

Access tiers overview (includes Cold tier details): https://learn.microsoft.com/azure/storage/blobs/access-tiers-overview?tabs=azure-portal#cold-access-tier

Immutable storage overview (confirms support across all tiers): https://learn.microsoft.com/azure/storage/blobs/immutable-storage-overview

Summary of access tiers (Hot, Cool, Cold, Archive comparison): https://learn.microsoft.com/azure/storage/blobs/access-tiers-overview?tabs=azure-portal#summary-of-access-tier-options

Pleaseand “up-vote” wherever the information provided helps you, this can be beneficial to other community members.

Chris Heys 5 Reputation points

2026-05-20T09:56:18.5766667+00:00

Hi Vallepu. The Microsoft Learn module page I shared has already been mostly updated to reference the Hot, Cool, Cold, and Archive tiers. However, this particular page refers to all four tiers in some places and only three in others.

When reading it for the first time, this gave the impression that the older three tiers were being distinguished from the Cold tier — particularly where it states that “storage is implemented differently” for those tiers. I appreciate that this is not the intended meaning.

Thank you for logging the request to update the article; I’m sure that will help remove the ambiguity for future readers.
Chris Heys 5 Reputation points

2026-06-25T17:21:03.8066667+00:00

Just a note that the article has not yet been updated.
Vallepu Venkateswarlu 10,590 Reputation points Microsoft External Staff Moderator

2026-06-26T12:16:18.4033333+00:00

You can submit a feedback request for the specific document. The documentation team will review the feedback and update the document if necessary.

Answer 2

The Cold tier is an additional Azure Blob Storage access tier and is supported alongside Hot, Cool, and Archive for block blobs. Any Learn content that describes immutable storage or access tiers only as “Hot, Cool, and Archive” without mentioning Cold is now incomplete and should be updated to reflect the four online/offline tiers:

Hot – online, frequently accessed data, highest storage cost, lowest access cost.
Cool – online, infrequently accessed data, minimum recommended retention 30 days.
Cold – online, rarely accessed data that still needs fast retrieval, minimum recommended retention 90 days, lower storage but higher access cost than Cool.
Archive – offline, rarely accessed data with flexible latency (hours), minimum recommended retention 180 days.

Cold is an online access tier like Hot and Cool and participates in the same general access-tier model and cost/retention behavior (including early deletion penalties when moved or deleted before the minimum retention period).

For immutable storage scenarios, any guidance that lists only Hot, Cool, and Archive as the available tiers should be revised to include Cold wherever online access tiers are discussed.

References: