DR strategies, AWS Backup and RTO/RPO: DOP-C02 study notes and practice questions
What to know about DR strategies, AWS Backup and RTO/RPO for the DOP-C02 exam, from the Resilient Cloud Solutions domain (15% of the exam guide), then 3 free questions to test it. Part of the DOP-C02 study guide.
An insurance firm runs its claims platform in one Region. The platform uses an Auto Scaling fleet of EC2 instances, an Aurora cluster and an Application Load Balancer, and the firm has set a recovery time objective of 15 minutes and a recovery point objective of about five minutes.
The firm needs a second Region that already holds replicated data and has the application stack defined and deployable. During a regional event, a reduced-capacity copy of the platform must start serving claims traffic within five minutes, and the rest of the fleet must scale up to full capacity within the 15-minute objective.
The firm wants the lowest cost that still meets these targets, and it wants no human approval in the failover path.
Which DR strategy meets these requirements?
Choose one answer.
AA. Backup and restore, with nightly AWS Backup copies to the second Region and an infrastructure template that the team runs after a regional outage to rebuild the platform.
BB. Pilot light, with the Aurora data replicated continuously to the second Region and only the database running there, and the Auto Scaling fleet and load balancer created during a failover.
CC. Multi-site active-active, with full copies of the fleet running in both Regions and traffic split across them, so that either Region can absorb the whole load immediately.
DD. Warm standby, with a scaled-down but running copy of the fleet and load balancer in the second Region, Aurora replicated there, and automatic scale-out during a failover.
D. Right: Correct. The reduced-capacity copy already serves traffic, so the five-minute target can be met, and automatic scaling brings the rest of the fleet up within the 15-minute objective. Continuous replication keeps the data within the recovery point. Learn more: Disaster recovery options in the cloud (opens in a new tab)
Explanation
A warm standby keeps a scaled-down copy of the serving stack running in the second Region, with continuous data replication, so a failover can serve reduced traffic within minutes and scale up within the recovery time objective. Backup and restore and pilot light start too late for the serving tier, and active-active costs more than the firm wants.
A logistics company stores shipment records in Amazon DynamoDB and Amazon EFS, and it runs a nightly AWS Backup plan for both. The backups are kept in a vault in the primary Region only.
The company's disaster recovery policy requires a copy of every backup in a second Region, with the same retention, and it requires the team to prove each quarter that restores from the copies actually work.
The team wants the copies and the restore tests to run on schedule, with no custom scripts to maintain.
Which TWO actions meet these requirements? (Choose two.)
Choose two answers.
AA. Write a Lambda function that runs each night, starts DynamoDB exports to S3 and copies the EFS file system with rsync to a second Region, and deletes the copies after 35 days.
BB. Enable DynamoDB point-in-time recovery on the tables, since it restores the tables to any second in the retention window in the same Region.
CC. Add a copy action to the backup plan that copies each recovery point to a vault in the second Region with the same retention, so that every nightly backup has a copy there.
DD. Configure an S3 replication rule for the backup vault's bucket, so that the S3 objects behind the EFS backups replicate to a second Region without any action from the backup plan.
EE. Create a restore testing plan in the second Region that restores a randomly selected recovery point from that Region's vault on a quarterly schedule and records the result of each test.
Show the answer and explanation
Answers: C, E
A. Wrong: This copies the data, but the team would write and maintain the export, copy and retention logic. Exports and rsync copies also do not give AWS Backup's recovery points and restore records.
E. Right: Correct. AWS Backup restore testing plans restore recovery points on a schedule and record the outcome, which provides the quarterly proof the policy requires. No scripts are needed. Learn more: Restore testing (opens in a new tab)
Explanation
An AWS Backup plan can copy each recovery point to a vault in a second Region with retention set in the plan, and a restore testing plan restores selected recovery points on a schedule and records the results. Together they meet the copy and quarterly-proof requirements with no scripts. Custom exports, point-in-time recovery and S3 replication rules do not provide both.
An airline's loyalty program stores member points in a DynamoDB table with point-in-time recovery turned on. A faulty release last night wrote incorrect point totals to about 40,000 members between 2:00 and 2:20 a.m.
The operations team needs to recover the table to the state it had at 1:55 a.m. without restoring the whole table over the live one, so that the team can compare and repair the affected items.
The team wants the fastest recovery that does not require exporting or re-importing data by hand.
Which approach meets these requirements?
Choose one answer.
AA. Restore the most recent nightly export from Amazon S3 into a new table, then copy the affected items back into the live table with a script that the team writes for the repair.
BB. Restore the table to a new table at the timestamp 1:55 a.m. using point-in-time recovery, and compare the restored table with the live table to repair the affected items.
CC. Create an on-demand backup of the live table now, and restore that backup over the live table, so that the members' data is returned to the state the backup captured.
DD. Replay the DynamoDB Streams records from 1:55 a.m. onward into the live table with a Lambda function, reversing each change that the faulty release made.
B. Right: Correct. Point-in-time recovery restores the table to a chosen second within the retention window as a new table, which leaves the live table untouched for comparison. The team can then repair the affected items. Learn more: Point-in-time backups for DynamoDB (opens in a new tab)
DynamoDB point-in-time recovery restores a table to a chosen time within the retention window, creating a new table that leaves the live table in place. The team can compare the two and repair the affected items. Exports, fresh backups and stream replay either predate the fault or require custom reversal code.
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