Understanding Redundancy Options for Azure Storage Accounts

Introduction

Azure Storage provides various redundancy options to ensure our data is safe, highly available, and durable. Each redundancy option caters to different needs, such as protection against data loss due to hardware failures, data center outages, or regional disasters. This blog will break down the available options and their compatibility with Azure Storage account types.

Redundancy Options Overview

Here’s a quick explanation of the redundancy options:

• Locally Redundant Storage (LRS): Data is replicated three times within a single data center. Cost-effective but doesn't protect against data center outages.

• Zone-Redundant Storage (ZRS): Data is replicated across three separate availability zones within the same region. Protects against data center failures.

• Geo-Redundant Storage (GRS): Data is replicated within the primary region (like LRS) and asynchronously replicated to another region for disaster recovery.

• Read-Access Geo-Redundant Storage (RA-GRS): Like GRS but also allows read access to the secondary region.

• Geo-Zone-Redundant Storage (GZRS): Combines the advantages of ZRS and GRS, providing zone-level redundancy in the primary region and replicating data to another region.

• Read-Access Geo-Zone-Redundant Storage (RA-GZRS): Like GZRS but enables read access to the secondary region.

Redundancy Options by Storage Account Type

The following table outlines the redundancy options supported by each Azure Storage account type:

Which Redundancy Option Should You Choose?

• LRS: Ideal for non-critical applications where cost savings are a priority.
• ZRS: Use for high availability within a region, protecting against data center failures.
• GRS: Suitable for disaster recovery where replication to another region is necessary.
• RA-GRS: Great for read-heavy applications requiring high availability even in disasters.
• GZRS/RA-GZRS: Best for mission-critical applications needing the highest durability and availability.

Key Takeaways

Azure's redundancy options give you the flexibility to balance cost, performance, and durability based on your application needs. When choosing, consider your application’s tolerance for downtime, data criticality, and budget. For most general use cases, Standard General-Purpose v2 storage accounts provide the widest range of redundancy options.

See also

The blog post: Understanding azure infrastructure regions availability zones and data centers

The blog post: Understanding ra-grs and ra-gzrs in azure storage accounts