A storage class, called an access tier in Azure Storage, matches data to how quickly it must be available and how much it should cost to keep. Choosing the cheapest-looking tier without considering access can mean slow retrieval or a larger bill. Blob Storage and Azure Files offer different tier choices. section 5.3.1 section 5.4
For blobs, choose by how urgently the files are needed:
- Hot keeps frequently used or immediately needed files readily available, such as customer orders. section 5.3.1
- Cool suits infrequently accessed files that are not urgent, such as images for a monthly newsletter. section 5.3.1
- Archive is offline and cheap for rarely needed backups or retained raw data, but retrieval can take hours. section 5.3.1
Azure file shares have a different menu. Transaction optimized, the default, favors workloads with many transactions; Hot sits between it and Cool on storage and transaction costs. Cool has the lowest storage cost and highest transaction cost of those three HDD-backed tiers. Premium uses SSDs for low latency, but bills for allocated capacity rather than space used: a 100 GiB Premium share holding 50 GiB is billed for 100 GiB. A Premium share cannot be changed to a non-Premium tier, or vice versa. section 5.4 section 5.4.1
PS C:\> New-AzRmStorageShare -ResourceGroupName BanningRG -StorageAccountName banningstorage -Name bannedfiles -AccessTier TransactionOptimized -QuotaGiB 1024
This PowerShell command creates a file share with an explicit TransactionOptimized access tier and a 1024 GiB quota. section 5.4
Tier choice is not always a one-time decision for blobs. Life cycle management rules can move data between access tiers as usage changes, delete outdated data, and help meet retention requirements. For an image-processing application that may accumulate many images, reviewing tiers is a practical production cost check. section 9.5 section 2.3.4
