Question

Difficulty: MediumData Redundancy and High Availability

A financial software company is migrating an on-premises document management system to Azure. The system requires a shared file storage solution accessible over SMB that can support an active-active configuration across multiple compute instances. The solution must guarantee single-digit millisecond latency for file operations and must survive the failure of an entire datacenter in the primary region without any data loss or application downtime. Which storage tier and redundancy option should you recommend to meet these requirements?

  1. A
    Premium Azure Files configured with Locally Redundant Storage (LRS)
  2. Premium Azure Files configured with Zone-Redundant Storage (ZRS)Answer
  3. C
    Premium Azure Files configured with Geo-Redundant Storage (GRS)
  4. D
    Standard Azure Files configured with Zone-Redundant Storage (ZRS)

Answer

Premium Azure Files configured with Zone-Redundant Storage (ZRS)
The correct answer is Premium Azure Files configured with Zone-Redundant Storage (ZRS). Premium Azure Files is backed by SSDs to guarantee the required single-digit millisecond latency. Configuring it with ZRS ensures data is replicated synchronously across three availability zones, allowing it to survive a datacenter failure in the primary region without downtime or data loss.

Step-by-Step Solution

1
Identify the protocol and latency requirements
The application requires an SMB-compatible shared file system with single-digit millisecond latency, which dictates the use of the Premium tier of Azure Files (backed by SSDs).
Standard Azure Files uses HDD storage and does not guarantee the low latency required for metadata and file operations.
2
Identify the high availability and disaster resilience requirements
The storage must survive the failure of an entire datacenter in the primary region, pointing to Zone-Redundant Storage (ZRS).
ZRS replicates data synchronously across three physical facilities (Availability Zones) in the region.
3
Verify storage account and tier limitations
Confirm that Premium Azure Files supports ZRS but does not support GRS.
Premium file shares are deployed in FileStorage accounts, which only support LRS and ZRS redundancy options.

Key Concept

Premium Azure Files supports only LRS and ZRS configurations, and ZRS must be chosen to satisfy both low-latency performance and zone-outage resilience.
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