AZ-305 Practice Question 48: Application Caching Layer
Microsoft Azure Solutions Architect Expert (AZ-305) · Test 5 · question 8 of 10
A retailer's product catalog site repeatedly reads the same rows from Azure SQL Database and keeps shopping-cart session state in a database table. Latency is poor at peak. The redesign needs a managed in-memory cache that supports the cache-aside and session-store patterns, is replicated for high availability, is reachable over a private endpoint, and is not built on a service with an announced retirement.
Which service should you recommend?
Show answer and explanation
Answer:
Azure Managed Redis is the current in-memory data store service, built on Redis Enterprise and operated by Microsoft. Its documented key scenarios include the data cache (cache-aside) and session store patterns that this site needs, and every tier provides replication and failover, high availability, data encryption in transit over a private endpoint, and network isolation through Private Link.
Option B fails the last requirement in the stem. Azure Cache for Redis has announced a retirement timeline for all SKUs and Microsoft recommends moving existing instances to Azure Managed Redis; the Basic tier is additionally a single-VM cache with no SLA, intended for development and test.
Option C uses a database as a cache. Cosmos DB is a low-latency operational store, but it is disk backed and priced per provisioned request unit, so it is neither the cheapest nor the fastest way to hold hot rows and session state, and it leaves the retailer with the same read volume, just against a different database.
Option D does not survive scale-out. Each instance keeps its own copy, so cache hit rates fall as instances are added, entries go stale independently, and session state is lost whenever an instance recycles or a user is routed elsewhere. A distributed cache exists precisely to avoid this.
Reference: What is Azure Managed Redis?