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.