Exam AWS Certified Solutions Architect - Associate SAA-C02 topic 1 question 287 discussion

In my opinion it has to be A. They are talking about "LEAST amount of downtime". Therefore B and C must be ruled out because they involve some downtime while executing the CloudFormation template. D is like B in a way: both have the same resources already created in the DR region but D is using a contrived and artificial method of switching the DNS configuration instead of the natural one: Failover routing. Have a look at: https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/routing-policy.html#routing-policy-failover

Maybe this link can help: https://docs.aws.amazon.com/wellarchitected/latest/reliability-pillar/plan-for-disaster-recovery-dr.html For me, option A means having the resources in the second region already created (active-active strategy).

I guess maybe Cloudwatch and Lamda can detect EC2 fault or downplay prior to its collapse to failover

C - Pilot light (RPO in minutes, RTO in hours): Replicate your data from one region to another and provision a copy of your core workload infrastructure. Resources required to support data replication and backup such as databases and object storage are always on. Other elements such as application servers are loaded with application code and configurations, but are switched off and are only used during testing or when Disaster Recovery failover is invoked.

The questions asks about how the set up should be created so with minimum downtime the traffic can be swinged to other site and not about how to create the setup. If how to create the set up will be point to B or D.

I think it has to be A.

Minimum Downtime is with "Failover routing policy".

A Aaaaaaaa

Its A 100%

IMO: D is fastest as a active/active hot standby. R53 failover is only good for active passive and might take a lot of time. CFN can take hours. In any, info (R53, healthchecks,...) is missing. link: https://docs.aws.amazon.com/whitepapers/latest/disaster-recovery-workloads-on-aws/disaster-recovery-options-in-the-cloud.html

My answer is D.

AS They are talking about "LEAST amount of downtime and Cloudformation can’t replace ASG

must be (a) can't be (d) because that is manually creating a solution that (a) gives us for free

I have one question. it never said that this configuration is using route 53. if you are not using it, how can we use route 53 to point to new disaster recovery Region ?

Answer A Cloudformation can’t replace ASG. B and C are missing ASG, they won't scale out once setup. D uses manual way to do DNS failover

check this link my ans is D. https://aws.amazon.com/blogs/compute/building-a-dynamic-dns-for-route-53-using-cloudwatch-events-and-lambda/

Should be A. See the URL below, explaining health check function of Route 53. https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/dns-failover.html