A company runs a stateful application on Compute Engine with persistent disks. They want to ensure data durability across a zone failure. What is the best approach?
Regional PDs replicate data across zones with synchronous writes, ensuring durability.
Why this answer
Regional persistent disks (RPDs) synchronously replicate data between two zones in the same region, providing an RPO of zero and automatic failover without application-level changes. This ensures data durability across a zone failure while maintaining consistent performance and low latency.
Exam trap
Google Cloud often tests the distinction between synchronous replication (regional persistent disks) and asynchronous backup (snapshots), leading candidates to choose snapshots for durability when they actually need zero RPO across a zone failure.
How to eliminate wrong answers
Option A is wrong because replicating data at the application level adds complexity, latency, and requires custom code, whereas Compute Engine offers a managed, synchronous replication solution. Option B is wrong because Google Cloud NetApp Volumes is a third-party service that is not natively integrated with Compute Engine for this use case and introduces additional cost and management overhead. Option D is wrong because regular snapshots stored in a multiregional bucket provide point-in-time recovery but have an RPO of minutes to hours and do not offer synchronous replication, so data written between snapshots is lost during a zone failure.