Answer: geo-redundant storage (GRS)

## Analysis of the Question Requirements The question specifies two key requirements: 1. **Data availability for read workloads in a secondary region IF an outage occurs in the primary region** 2. **Minimize costs** ## Evaluation of Storage Redundancy Options ### Option A: Geo-redundant storage (GRS) - **Functionality**: GRS replicates data asynchronously to a secondary geographic region for disaster recovery protection. In the event of a regional outage, Microsoft or the customer can initiate a failover to make the secondary region available for both read and write operations. - **Cost consideration**: GRS is less expensive than RA-GRS because it doesn't provide continuous read access to the secondary region. - **Alignment with requirements**: The question specifically states "IF an outage occurs" - GRS provides exactly this capability at a lower cost than RA-GRS. ### Option B: Read-access geo-redundant storage (RA-GRS) - **Functionality**: RA-GRS provides the same geo-replication as GRS but adds continuous read access to the secondary region, even when the primary region is fully operational. - **Cost consideration**: RA-GRS is more expensive than GRS due to the additional read capability. - **Alignment with requirements**: While RA-GRS does provide read access during outages, it offers more capability than required (continuous secondary read access) at a higher cost, which contradicts the cost minimization requirement. ### Option C: Zone-redundant storage (ZRS) - **Functionality**: ZRS replicates data across multiple availability zones within a single region, providing protection against zone-level failures but NOT regional outages. - **Cost consideration**: ZRS is typically more expensive than GRS but less than RA-GRS. - **Alignment with requirements**: ZRS does NOT provide cross-region redundancy, so it cannot meet the requirement for secondary region availability during regional outages. ### Option D: Locally-redundant storage (LRS) - **Functionality**: LRS replicates data within a single data center, providing the lowest level of redundancy. - **Cost consideration**: LRS is the cheapest option. - **Alignment with requirements**: LRS provides no cross-region protection and cannot meet the secondary region availability requirement. ## Conclusion **GRS (Option A)** is the optimal choice because: - It provides the required cross-region replication for disaster recovery - It enables read access in the secondary region **only when needed** (during outages), which aligns perfectly with the "IF an outage occurs" requirement - It is less expensive than RA-GRS, satisfying the cost minimization requirement - The question does not require continuous read access to the secondary region, which is the key differentiator (and additional cost) of RA-GRS RA-GRS would be over-provisioning for this scenario since the requirement specifically calls for secondary region read access only during outages, not continuous secondary region read capability.