Exam AWS Certified Solutions Architect - Professional SAP-C02 topic 1 question 125 discussion

CDE. RDS Failover typically takes 60-120 seconds, while Aurora failover completes within 30 seconds. ElastiCache is for reducing latency, not for failover.

RDS Proxy with Aurora are the best combination for less than "20 sec" failover time... According to this article RDS Proxy can reduce the failover time of Aurora by 79% while it can reduce RDS failover time by only 32%: https://aws.amazon.com/blogs/database/improving-application-availability-with-amazon-rds-proxy/

for multiple chose answer, if i select 2of3 right, in this case the whole quest will be wrong or what?

C. Use RDS Proxy in front of the database. D. Migrate the database to Amazon Aurora MySQL. E. Create an Amazon Aurora Replica.

A and B don't contribute to reducing response time in failover scenarios. D is required for faster failover. E is required to support D. F doesn't reduce failover time. C, finally, is the remaining option. It doesn't hurt, and can contribute to faster failover, though it is not the most important factor here - the switch to Aurora with an Aurora read replica is.

Anyone can share why choosing E? I know we have to choose 3. isn't it weird? Aurora already has replicas natively. Why creating another one?

Option C, D and E

C+D+E provides the 'fastest' failover with the options available: - Aurora MySQL is Multi-AZ by design: During failover it will promote a Replica to primary or create a Primary instance - Creating a Replica provides the option to have something to failover to - Using an RDS Proxy further reduces failover time and provides 'transparent' failovers as well (It manages DNS changes) The argument against Caching (options A or B) is that it doesn't accelerate failing over to a different instance. Cache misses and write operations will produce exceptions because there is no instance to query. Moreover, there is no information in the question to choose between either caching option, i.e. Both options can be created starting from an Aurora DB Cluster settings - https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/creating-elasticache-cluster-with-RDS-settings.html

CDE, agree with other comments

The trick seems to be that the RDS proxy handles DNS updates quickly. While if you don't use it, you are at the mercy of the host to update its DNS cache.

CDE is the best choice

CDE. I would have said F, but the question asks for a combination of steps, so its looking for the Aurora replica and not the MySQL RDS replica

C for sure as connection pooling helps quick re connect. There is no preference for A or B cache solution based on the question. So, A,B are eliminated. so three correct options should be in others. If you choose Aurora only, three answers will be met :-) C,D,E

C D and E

RDS read replica auto failover takes approx 35 seconds hence, BCF does not satisfy under 20 seconds failover requirement. https://aws.amazon.com/rds/features/multi-az/#:~:text=Amazon%20RDS%20Multi%2DAZ%20with%20two%20readable%20standbys,-Automatically%20fail%20over&text=Automatically%20failover%20in%20typically%20under,and%20with%20no%20manual%20intervention.

The correct answer is D, E and C: Migrate the database to Amazon Aurora MySQL. - Create an Amazon Aurora Replica. - Use RDS Proxy in front of the database. - These options are correct because they address the requirement of reducing the failover time to less than 20 seconds. Migrating to Amazon Aurora MySQL and creating an Aurora replica can reduce the failover time to less than 20 seconds. Aurora has a built-in, fault-tolerant storage system that can automatically detect and repair failures. Additionally, Aurora has a feature called "Aurora Global Database" which allows you to create read-only replicas across multiple AWS regions which can further help to reduce the failover time. Creating an Aurora replica can also help to reduce the failover time as it can take over as the primary DB instance in case of a failure. Using RDS proxy can also help to reduce the failover time as it can route the queries to the healthy DB instance, it also helps to balance the load across multiple DB instances.

The correct answer is B, C and F. Using Amazon ElastiCache for Redis in front of the database (Option B) will help to reduce the failover time by caching the frequently-used data, so that it can be quickly served from the cache rather than having to be retrieved from the database during a failover. Using RDS Proxy in front of the database (Option C) will help to reduce the failover time by managing the connections to the RDS DB instance, so that it can quickly route traffic to the new primary instance during a failover. Creating an RDS for MySQL read replica (Option F) will help to reduce the failover time by having a read-only copy of the database running in parallel with the primary instance, so that it can take over as the primary instance in the event of a failover. Option A and D are not relevant in this case as the question is asking specifically about reducing failover time for an RDS for MySQL database.