Azure Storage Accounts and Services

Quick Answer: Azure Storage provides Blob (objects), File (SMB shares), Queue (messaging), and Table (NoSQL) services. Storage accounts have redundancy options from LRS (3 copies, 1 data center) to GZRS (6 copies, cross-zone and cross-region). Blob Storage has Hot, Cool, Cold, and Archive tiers.

Azure Storage Account

A storage account provides a unique namespace in Azure for your data. Every object you store has an address that includes your unique account name. The combination of account name and service endpoint forms a URL:

Storage Account Types

On the Exam: Standard general-purpose v2 is the recommended account type for most scenarios. It supports all storage services and all redundancy options. Only use Premium accounts when you need SSD performance.

The Four Azure Storage Services

1. Azure Blob Storage (Binary Large Objects)

Blob Storage is Azure's object storage solution, designed for storing massive amounts of unstructured data — text, binary data, images, videos, backups, logs.

Blob types:

Access tiers (optimize cost by data access frequency):

On the Exam: Archive tier data is OFFLINE and must be "rehydrated" to Hot or Cool before it can be accessed. Rehydration can take hours. This is the cheapest storage option but has the highest access cost and latency.

2. Azure Files (File Shares)

Azure Files provides fully managed file shares in the cloud, accessible via the SMB (Server Message Block) and NFS (Network File System) protocols.

Key features:

• SMB and NFS — Mount file shares on Windows, macOS, and Linux just like a local network drive
• Shared access — Multiple VMs can read and write to the same file share simultaneously
• Azure File Sync — Sync on-premises Windows file servers with Azure Files for hybrid access
• Snapshots — Point-in-time read-only copies of file shares

Use cases:

• Replacing or supplementing on-premises file servers
• "Lift and shift" applications that use SMB file shares
• Shared storage for applications running across multiple VMs
• Storing configuration files, diagnostic logs, and metrics

3. Azure Queue Storage

Queue Storage provides a messaging queue for asynchronous communication between application components. Messages can be up to 64 KB in size.

Use cases:

• Decoupling application components for independent scaling
• Creating a work backlog for asynchronous processing
• Passing messages between web role and worker role in a microservices architecture

4. Azure Table Storage

Table Storage is a NoSQL key-value store for storing large amounts of structured, non-relational data.

Key features:

• Schemaless — Each entity can have different properties
• Massive scale — Store terabytes of data
• Fast — Low-latency access for key-value lookups

Note: For new NoSQL projects, Microsoft recommends Azure Cosmos DB Table API over Table Storage, as it provides higher performance, global distribution, and additional features.

Storage Redundancy Options

Azure replicates your data to protect against planned and unplanned failures. Understanding redundancy options is critical for the AZ-900:

Primary Region Redundancy

Primary + Secondary Region Redundancy

Read Access to Secondary Region

• RA-GRS — Read-access geo-redundant storage (read from secondary anytime)
• RA-GZRS — Read-access geo-zone-redundant storage (highest availability)

On the Exam: For maximum durability, choose RA-GZRS. For minimum cost, choose LRS. For region failure protection, choose GRS or GZRS. If the question mentions "availability zone failure," ZRS or GZRS is the answer.

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