A vs B: Backups run in intervals -> will lose data up to the last backup point -> cannot achieve low RPO. B is better solution C vs D: D works because the ASG maintains capacity to 1, that means resource are always at least available for failover. C is more costly. E: when you see manual, you run

Global Aurora creates a read only copy in another region that can be manually promoted to R/W for failover, In regards to the scaling group, I'd have to say that having on VM running in al DR region(s) with minimum capacity of 1, but maximum capacity that matches prod means the scaling and load balancing will automatically grow without intervention as soon as Route 53 record points to the failover region. This should not cost 1 cent more to do this, and it eliminates an extra manual step during failover. I can't find documentation to back this up, but I'm sure it's the right answer because it makes sense and simplifies/automates a critical step.

Option B is selected because Aurora Global Databases provide cross-region replication with typically less than 1 second of replication lag, which supports the 15-minute RPO requirement1. This option also allows for quick promotion of the secondary region in case of a disaster, aligning with the 15-minute RTO2. Option C is chosen because having an ALB and an Auto Scaling group pre-configured in the DR region ensures that the application can be quickly redirected and scaled in case of a disaster, meeting the 15-minute RTO2. This setup avoids the time and potential errors associated with manual creation during a failover.

I tend to choose BD because is a much cost-effective choice than to keep the same configuration in the DR region. I also believe that 15 minutes are enough to scale that ASG from one to the desired value so the app can failover within that period of time. Why not C? Because essentially keeping the same configuration of an application in another region implies huse costs (multi-site approach). Please have a look over these DR strategies and see for yourselves the difference between the Warm Standby and the Active/Active approach. Given the requirement of 15 minutes, I'd say a Warm Standby in this case would be enough.

specifically for C vs D yall it ask for the most cost effective way. if they have the same configuration it will 2x their cost vs just having the min, max, and desired instanced to 1. Because it even has a back up instance means there is fail over. Which is why D is better than C

B. Configure the Aurora cluster to replicate data to the DR Region by using the Aurora global database option. Aurora global database allows you to replicate your Aurora database across AWS Regions with minimal replication lag. By setting up the Aurora global database option, you ensure that data is continuously being replicated to the DR Region, which helps meet the Recovery Point Objective (RPO) of 15 minutes. D. Configure the DR Region with an ALB and an Auto Scaling group. Set the Auto Scaling group's minimum capacity, maximum capacity, and desired capacity to 1. By configuring the DR Region with an ALB and an Auto Scaling group with minimum, maximum, and desired capacity set to 1, you ensure that the infrastructure is in place and ready to receive traffic in case of a failover event. Running just one instance will help reduce costs in the DR Region during normal operations while meeting the Recovery Time Objective (RTO) of 15 minutes.

A D MOST cost-effectively?