AZ-900 Describe Azure architecture and services Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  Zone-Redundant Storage (ZRS)

  Why it's wrong here

  Zone-Redundant Storage (ZRS) synchronously replicates your data across three Azure availability zones within the selected region, and each availability zone is a physically separate data center. Because it spans multiple data centers and provides higher availability than the single-datacenter requirement, it does not qualify as the lowest-cost option and is not the correct answer.

• ✗

  Geo-Redundant Storage (GRS)

  Why it's wrong here

  Geo-Redundant Storage (GRS) copies data asynchronously to a secondary region that is typically hundreds of miles away, in addition to keeping three copies in the primary region. This cross-region replication incurs additional egress and storage costs, and the secondary region is not a single data center, so it cannot satisfy the stated requirement for minimal cost within one data center.

• ✓

  Locally Redundant Storage (LRS)

  Why this is correct

  Locally Redundant Storage (LRS) creates three synchronous replicas of your data within a single physical data center in the primary region. It is the lowest-cost redundancy tier because it avoids the extra capacity and network costs of replicating to other zones or regions, making it the correct choice when the requirement is minimal cost and single-datacenter placement.

• ✗

  Read-Access Geo-Redundant Storage (RA-GRS)

  Why it's wrong here

  Read-Access Geo-Redundant Storage (RA-GRS) provides the same geo-replication as GRS but additionally enables read access to data in the secondary region. This secondary region serves as a separate geographic location, not a single data center, and its read access feature and added geographic replication make it significantly more expensive than LRS, so it is incorrect for a low-cost, single-datacenter scenario.