SOA-C03 practice question: Disaster recovery strategies

Reliability and Business Continuity A free question from our original SOA-C03 practice exam. Try it, then open the answer to see why each option is right or wrong.

A solar installer runs its customer portal on EC2 instances and an Amazon Aurora PostgreSQL database in one Region. Its new disaster recovery requirements are an RPO of under one minute and an RTO of under one hour if the Region fails. The infrastructure is defined in CloudFormation templates. The finance team wants the LOWEST ongoing cost that meets both targets. Which strategy should a CloudOps engineer implement?

Choose one answer.

A. Back up the database and EC2 volumes with AWS Backup, copy recovery points to the second Region every night, and restore them after a disaster.
B. Run a full-size copy of the portal in the second Region behind Route 53 latency routing, with both Regions serving users all the time.
C. Add the second Region to an Aurora global database, keep application servers off there, and launch them from the templates during a failover.
D. Run a scaled-down but working copy of the portal in the second Region that receives no traffic, and scale it up during a failover.

Show the answer and explanation

Answer: C

A. Wrong: Backup and restore is the cheapest strategy, but nightly copies give an RPO of up to 24 hours. Restoring a database and fleet would also take longer than the RTO in most cases. Learn more: Disaster recovery options in the cloud (opens in a new tab)
B. Wrong: Active/active meets both targets easily but doubles the running infrastructure. It costs far more than the requirements need. Learn more: Disaster recovery options in the cloud (opens in a new tab)
C. Right: Correct. This is a pilot light design. Aurora global database replication usually lags by about a second, which meets the RPO, and launching the stack from templates fits an RTO of under an hour. Learn more: Using Amazon Aurora Global Database (opens in a new tab)
D. Wrong: Warm standby meets the targets, but it keeps application servers running all the time. Pilot light reaches an RTO under an hour for less ongoing cost. Learn more: Disaster recovery options in the cloud (opens in a new tab)

Explanation

Disaster recovery strategies trade cost against recovery speed. Pilot light keeps the data layer replicating continuously and the rest of the stack switched off, ready to launch from infrastructure as code, which suits a short RPO and an RTO of tens of minutes. Backup and restore is too slow, and warm standby and active/active cost more than the targets require.

SOA-C03 practice question: Disaster recovery strategies

Explanation

Study

Keep practicing