SAA-C03 practice question: Disaster recovery strategies (2 of 2)
Design Resilient Architectures A free question from our original SAA-C03 practice exam. Try it, then open the answer to see why each option is right or wrong.
A payments company runs an Amazon Aurora MySQL cluster in eu-west-2.
A new regulation requires that, if the whole Region becomes unavailable, the database can be running in eu-central-1 within 10 minutes and lose no more than 5 seconds of committed transactions. Replication must not add noticeable load to the primary cluster, and the small operations team wants the LEAST operational overhead.
Which solution meets these requirements?
Choose one answer.
AA. Use AWS Backup with continuous backups for the cluster, and a rule that copies a recovery point to a vault in eu-central-1 every hour.
BB. Add two Aurora Replicas in other Availability Zones of eu-west-2, and rely on Aurora's automatic failover to promote one of them.
CC. Add eu-central-1 to an Aurora global database as a secondary cluster, and run a global database failover if eu-west-2 is lost.
DD. Run AWS DMS ongoing replication from the cluster to a separate Aurora cluster in eu-central-1, and repoint the application after an outage.
Show the answer and explanation
Answer: C
A. Wrong: Cross-Region copies of continuous backups are periodic snapshots, so up to an hour of transactions could be lost, far beyond 5 seconds. Restoring a cluster from a snapshot also takes time. Aurora global database replicates continuously instead. Learn more: Copying continuous backups (opens in a new tab)
B. Wrong: Aurora Replicas give fast failover when an instance or Availability Zone fails, but they are all in eu-west-2. If the whole Region is unavailable, they go down with it. A secondary cluster in another Region is needed. Learn more: Replication with Amazon Aurora (opens in a new tab)
C. Right: Correct. A global database replicates at the storage layer with lag typically under a second and little impact on the primary. In a Regional outage, a failover promotes the eu-central-1 cluster to take writes, a managed step that fits the 10-minute target. Learn more: Using Amazon Aurora Global Database (opens in a new tab)
Aurora global database uses dedicated, storage-level replication to secondary Regions with latency typically under a second and little performance impact on the primary cluster. If the primary Region fails, a global database failover promotes a secondary cluster. Backups copied between Regions give a much larger RPO, same-Region replicas do not survive a Regional outage, and DMS adds load and operational work.
The secondary cluster in eu-central-1 stays about a second behind, and a global database failover promotes it if eu-west-2 is lost.
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