Answer: zone-redundant storage (ZRS)

## Explanation To ensure the Azure Data Lake Gen2 storage account remains available if a data center fails in the primary Azure region while minimizing costs, **Zone-Redundant Storage (ZRS)** is the optimal choice. ### Why ZRS is the Correct Answer: - **ZRS replicates data synchronously across three Azure availability zones** within the primary region. Each availability zone is a physically separate data center with independent power, cooling, and networking infrastructure. - If one data center fails, the data remains accessible from the other availability zones in the same region, meeting the availability requirement. - **ZRS is more cost-effective than geo-redundant options** (GRS/GZRS) because it doesn't involve cross-region replication, which incurs additional storage and bandwidth costs. ### Analysis of Other Options: - **A: Geo-Redundant Storage (GRS)** - While GRS provides cross-region replication and would maintain availability during a data center failure, it is more expensive than ZRS due to the additional replication to a secondary region. This violates the cost minimization requirement. - **B: Geo-Zone-Redundant Storage (GZRS)** - GZRS combines ZRS in the primary region with geo-replication to a secondary region. This provides the highest level of durability but is the most expensive option, making it unsuitable for cost minimization. - **C: Locally-Redundant Storage (LRS)** - LRS replicates data three times within a single data center. If that entire data center fails, all data replicas become unavailable, violating the availability requirement. While LRS is the cheapest option, it doesn't meet the business continuity needs specified in the scenario. ### Key Considerations: - The requirement specifically mentions **"a data center fails in the primary Azure region"** - not an entire regional outage. ZRS is designed precisely for this scenario. - **Cost minimization** is a critical constraint, eliminating the more expensive geo-redundant options. - Azure Data Lake Storage Gen2 inherits the redundancy capabilities of Azure Storage accounts, making ZRS the appropriate choice for this data lake implementation. ZRS provides the right balance of availability protection against data center failures while maintaining cost efficiency within the primary region.

Author: LeetQuiz Editorial Team