A company is running a batch application on Amazon EC2 instances. The application consists of a backend with multiple Amazon RDS databases. The application is causing a high number of reads on the databases. A solutions architect must reduce the number of database reads while ensuring high availability.

What should the solutions architect do to meet this requirement?

• A. Add Amazon RDS read replicas.
• B. Use Amazon ElastiCache for Redis.
• C. Use Amazon Route 53 DNS caching
• D. Use Amazon ElastiCache for Memcached.

Si el objetivo es reducir el numero de database reads, podemos entenderlo como que reduza el número de lectura en general por lo que podrías usar la opción B. El otro caso digamos que da mas high availability pero supuestamente elastic cache también la da.

A company needs to run a critical application on AWS. The company needs to use Amazon EC2 for the application’s database. The database must be highly available and must fail over automatically if a disruptive event occurs.

Which solution will meet these requirements?

• A. Launch two EC2 instances, each in a different Availability Zone in the same AWS Region. Install the database on both EC2 instances. Configure the EC2 instances as a cluster. Set up database replication.
• B. Launch an EC2 instance in an Availability Zone. Install the database on the EC2 instance. Use an Amazon Machine Image (AMI) to back up the data. Use AWS CloudFormation to automate provisioning of the EC2 instance if a disruptive event occurs.
• C. Launch two EC2 instances, each in a different AWS Region. Install the database on both EC2 instances. Set up database replication. Fail over the database to a second Region.
• D. Launch an EC2 instance in an Availability Zone. Install the database on the EC2 instance. Use an Amazon Machine Image (AMI) to back up the data. Use EC2 automatic recovery to recover the instance if a disruptive event occurs.

La alta disponiblidad se gestiona en la misma región no entre regiones. El failover entre regiones tiene que configurarloo de forma manual.

Cuando onfiguras las instancias como un cluster las configuras como si solo fueran una unidad

Opción A:

✔ Alta disponibilidad (HA) → Dos instancias en diferentes Availability Zones (AZs) aseguran que, si una AZ falla, la otra sigue operativa.