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GRS Redundancy vs GZRS Redundancy

For applications requiring high durability, you can choose to additionally copy the data in your storage account to a secondary region that is hundreds of miles away from the primary region. If your storage account is copied to a secondary region, then your data is durable even in the case of a complete regional outage or a disaster in which the primary region isn’t recoverable.

In this lecture, you will delve into two Azure storage redundancy options: Geo-Redundant Storage (GRS) and Geo-Zone-Redundant Storage (GZRS). The lecture discusses the necessity of high durability for applications and the means to achieve this by copying data to a secondary, far-removed region for resilience against regional outages or natural disasters.

The focus then shifts to explaining GRS, which involves synchronously copying data within a primary region and asynchronously to a secondary region, where it is once again stored with local redundancy. GZRS, on the other hand, is introduced as a service that synchronously copies data across three availability zones in the primary region, then asynchronously to a secondary region with subsequent local redundancy.

A key takeaway is the difference in how GRS and GZRS handle data replication in the primary region. Despite the similarities in the secondary region, the primary region replication strategy is what sets them apart.

Attention is given to the fact that in both GRS and GZRS, the secondary region’s data is inaccessible for read or write operations until a failover occurs. The lecture introduces Read-Access Geo-Redundant Storage (RA-GRS) and Read-Access Geo-Zone-Redundant Storage (RA-GZRS) as solutions to enable read access to data in the secondary region, especially during primary region outages.

Furthermore, the lecture covers the impressive durability guarantee of 16 nines (99.99999999999999%) for storage resources using these redundancy options over a year, and highlights how GZRS is recommended for applications requiring the utmost consistency, durability, availability, performance, and disaster recovery resilience.

Lastly, the lecture emphasizes that GZRS is only available for Standard General-Purpose V2 Storage Accounts but supports all Azure storage services. Before concluding, the lecture advises you to remember the key aspects of GRS and GZRS, understand their typical use cases, and be able to explain the functionalities of RA-GRS and RA-GZRS for exam preparedness.

© 2023 Thomas J Mitchell / TomTeachesIT