SOA-C02 Reliability and Business Continuity 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.

• ✗

  DynamoDB Accelerator (DAX)

  Why it's wrong here

  DynamoDB Accelerator (DAX) is an in-memory cache that sits in front of a single DynamoDB table to reduce read latency by serving strongly consistent reads from memory. However, DAX caches data only within one AWS Region and does not replicate, synchronize, or back up table contents to other Regions. Even if you launch DAX clusters in multiple Regions, each cluster reads from its own local DynamoDB table, so DAX by itself cannot provide cross-region disaster recovery or global low-latency access.

• ✓

  DynamoDB global tables

  Why this is correct

  DynamoDB global tables automatically replicate each item write to all selected AWS Regions, creating active-active replica tables with multi-region read and write capability. This cross-region replication gives users low-latency access because they can be served by a nearby replica, and it provides business continuity by allowing another Region to continue serving traffic during a Regional outage without manual data restore. Because every replica holds a full copy of the data, a Region failure is effectively transparent at the table level, assuming your application can reroute traffic.

• ✗

  DynamoDB Point-in-Time Recovery (PITR)

  Why it's wrong here

  Point-in-Time Recovery (PITR) continually backs up a table and lets you restore it to any second within the last 35 days, protecting against accidental writes/deletes. But PITR is a backup and restore mechanism, not a live replication feature: a restore creates a brand new table in the same Region, and the restore can take minutes to hours depending on size. Therefore PITR cannot serve global users with low latency or enable automatic failover during a Regional outage; it only gives you a recovery point, not continuous availability.

• ✗

  DynamoDB Auto Scaling

  Why it's wrong here

  DynamoDB Auto Scaling adjusts a table's provisioned read/write capacity based on observed utilization, preventing throttle errors during traffic spikes and saving cost during idle times. It affects only the capacity of a table in a single Region; it does not copy or distribute data anywhere, and it has no effect on data replication or geographic redundancy. Thus, Auto Scaling cannot improve latency for users in distant Regions or provide any form of disaster recovery when an entire Region becomes unavailable.