RDS Quiz
You are performing a Load Testing exercise on your application hosted on AWS. While testing your Amazon RDS MySQL DB Instance, you notice that your application becomes non responsive when you reach 100% CPU utilization. Your application is read-heavy. What methods will help scale your data-tier to meet the application’s needs? Choose three answers from the options given below.
A. Add Amazon RDS DB Read Replicas, and have your application direct read queries tothem.
B. Add your Amazon RDS DB Instance to an Auto Scaling group and configure yourCloudWatch metric based on CPU utilization.
C. Shard your data set among multiple Amazon RDS DB Instances.
D. Use ElastiCache in front of your Amazon RDS DB to cache common queries.
A. C. & D.
Amazon RDS Read Replicas provide enhanced performance and durability for database (DB) instances. This replication feature makes it easy to elastically scale out beyond the capacity constraints of a single DB Instance for read-heavy database workloads. You can create one or more replicas of a given source DB Instance and serve high-volume application read traffic from multiple copies of your data, thereby increasing aggregate read throughput.
For more information on Read Replicas, please refer to the link below.
https://aws.amazon.com/rds/details/read-replicas/
Sharding is a common concept to split data across multiple tables in a database.
Let us look at an example.
Virtual Shards
In this example, we assume our application currently doesn’t have enough load to need a physical shard for each category, but we want to plan ahead with growth in mind. To make future growth easier we make use ofvirtual shards. So our application code will act as if it has seven shards, but Hibernate will map those seven shards onto a smaller number of physical shards. Each physical shard will map to a MySQL database instance. By using this mapping we can distribute the load to best suit our needs. For our application assume that sports and entertainment generate as much load as the other five categories combined. These two categories will map to one physical shard and the other five categories will map to the other physical shard. The two physical shards will be mapped as follows.
For more information on sharding, please refer to the link below.
https://forums.aws.amazon.com/thread.jspa?messageID=203052
Amazon ElastiCache is a web service that makes it easy to deploy, operate, and scale an in-memory data store or cache inthe cloud. The service improves the performance of web applications by allowing you to retrieve information from fast, managed, in-memory data stores, instead of relying entirely on slower disk-based databases.
For more information on ElastiCache, please refer to the link below.
https://aws.amazon.com/elasticache/
Option B is not an ideal way to scale a database.
Option C is not an ideal choice to store data going into a database because of the message size.
Option F is invalid because the Multi-AZ feature is only a failover option.
