AZ-305 Practice Question 15: Storage Redundancy Selection
Microsoft Azure Solutions Architect Expert (AZ-305) · Test 2 · question 5 of 10
A public-sector agency stores 8 TB of case documents as block blobs in a general-purpose v2 storage account in West Europe. The design must meet these requirements:
- If one availability zone in West Europe is lost, the application must keep both reading and writing without any failover step. - If the entire West Europe region is lost, the data must still exist in another region. - The application never reads from the secondary region; during a regional outage the agency accepts initiating a failover. - Among the options that qualify, choose the least expensive.
Which redundancy option should you configure on the storage account?
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Answer:
GZRS writes each object synchronously across three or more availability zones in the primary region and then replicates asynchronously to the paired secondary region. That combination is what the two hard requirements ask for: with a GZRS account you can continue to read and write if an availability zone becomes unavailable, and the data survives a complete regional outage. Because the agency never reads the secondary, the read-access variant's extra cost buys nothing, which makes GZRS the cheapest option that qualifies.
Option A protects only against a zone failure. ZRS keeps all copies inside the primary region, so a regional disaster leaves no surviving copy; it fails the second requirement outright.
Option B would satisfy both failure scenarios but overshoots the third. RA-GZRS or RA-GRS exist to give applications read access to the secondary endpoint during an outage; the agency explicitly does not need that, and the read-access options cost more than their non-RA equivalents.
Option D is the closest wrong answer. GRS replicates to a second region, but inside the primary region it uses LRS, a single datacenter. Losing a zone therefore takes the account offline until an account failover is performed, which violates the "keep reading and writing with no failover step" requirement. The only difference between GRS and GZRS is how data is replicated in the primary region, and that difference is the one the requirements turn on.
Reference: Azure Storage redundancy