Cyber Intelligence
Azure Architecture and Services · 35-40% of exam

L9. Core Storage: Blob, Files, Queues, Tables, and Disk

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Azure Storage is the backbone of most Azure solutions. The AZ-900 exam tests the four storage types, access tiers, redundancy options, and when to use each.

Azure Storage Account

A storage account is the top-level container for Azure Storage services. It provides a unique namespace and lets you choose redundancy and performance tiers. The four core storage services:

Azure Blob Storage

Object storage for unstructured data: documents, images, video, backups, log files. Blobs are organized in containers. Access tiers (crucial for exam):

  • Hot: frequently accessed data; higher storage cost, lower access cost
  • Cool: infrequently accessed; lower storage cost, higher access cost (minimum 30-day retention)
  • Cold: rarely accessed; even lower storage cost (minimum 90-day retention)
  • Archive: rarely accessed; lowest cost, highest access latency (data is offline; must be rehydrated before access, minimum 180-day retention)
Use Blob for: backups, media streaming, static website hosting, data lakes.

Azure Files

Fully managed file shares accessible via SMB (Server Message Block) or NFS protocols. Can be mounted on Windows, Linux, and macOS. Use Files for: replacing on-premises file servers, lift-and-shift of applications that need shared file storage.

Azure Queue Storage

Message storage for asynchronous communication between application components. Messages can be up to 64 KB; queues can hold millions of messages. Use Queues for: decoupling application components, background processing, task queuing.

Azure Table Storage

NoSQL key-value store for structured, non-relational data. Fast and cost-effective for large amounts of semi-structured data. Use Tables for: web app user data, address books, device information (when Cosmos DB is overkill).

Azure Disk Storage

Managed disks attached to Azure Virtual Machines, analogous to a physical hard drive. Types: Ultra Disk (highest performance), Premium SSD, Standard SSD, Standard HDD.

Redundancy Options

OptionDescriptionCopies
LRSLocally redundant storage3 copies in one datacenter
ZRSZone-redundant storage3 copies across zones in one region
GRSGeo-redundant storageLRS + 3 copies in paired region
GZRSGeo-zone-redundant storageZRS + 3 copies in paired region
Exam tip: Archive tier data cannot be read immediately. It must be "rehydrated" to Hot or Cool first, which can take hours.

Exam Focus Points
  • Blob Storage is for unstructured object data; Hot/Cool/Cold/Archive tiers balance cost vs access speed
  • Archive tier data is offline and must be rehydrated before access; this can take hours
  • Azure Files provides SMB/NFS file shares mountable on Windows, Linux, and macOS
  • Queue Storage enables asynchronous decoupled messaging between application components
  • LRS = 3 copies in one datacenter; ZRS = 3 zones; GRS = LRS plus geo-redundant copy in paired region
Knowledge Check

1. A company stores compliance records that are rarely accessed and must be retained for 7 years at minimum cost. Which Azure Blob Storage access tier is most appropriate?

2. Which Azure storage redundancy option replicates data across availability zones within one region AND to a secondary paired region?

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