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?
Using Amazon ElastiCache for Redis reduces the number of database reads by storing frequently accessed data in memory, which is significantly faster than accessing data from an Amazon RDS database. Redis also supports high availability through read replicas and Multi AZ with failover capabilities, ensuring data availability even if the primary cache fails. This meets both requirements of reducing database reads and ensuring high availability.
Use ElastiCache to reduce reading and choose redis to ensure high availability.
Where is the high availability when the database fails and the cache time runs out? The answer is a.
Elasticache for Redis ensures high availability by using read replicas and Multi AZ with failover. It is also faster since it uses cache. https://docs.aws.amazon.com/AmazonElastiCache/latest/red-ug/AutoFailover.html
They run multiple databases
Right here: Redis has Multi AZ with Auto-Failover (in addition it got Read Replicas for HA)
Caching Frequently Accessed Data: ElastiCache allows you to store frequently accessed or computationally expensive data in-memory within the cache nodes. This means that when an application requests data, ElastiCache can provide the data directly from the cache without having to query the RDS database. This reduces the number of reads on the RDS database because the data is retrieved from the faster in-memory cache.
A vs B: A: reduce the number of database reads on main + high availability provide B: only reduce the number of DB reads so A wins
Why "only reduce the number of DB reads"? This is exactly what is asked. Elasticache for Redis can be HA (contrary to Elasticache for Memcached).
pentium75 is right.
Pretty sure answer is option B. You have to use a caching to 'reduce' database reads so read replica is out of option. The question mentions High availability so Redis is preferable than MemCached.
Elasticahe is NOSQL, A is the Answer!
B is incorrect because you have to explicitly enable and configure read replicas for Amazon ElastiCache for Redis. It's not enabled by default, and the choice says nothing about enabling read replicas for Elastichache for Redis. So B serves only the purpose of off-loading reads but not the HA one, while A will reduce the read requests for the main DB AND you can promote the read replica in case the main one fails, aka achieving high availability.
A cannot be write as more read replicas doesn't reduce the number of database queries. A is correct as cached data reduces the number of database queries as content is served from cache instead.
https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html "A read replica is a read-only copy of a DB instance. You can reduce the load on your primary DB instance by routing queries from your applications to the read replica."
B is right answer
A. Add Amazon RDS read replicas. Amazon RDS read replicas allow you to create one or more read-only copies of your RDS database instance. By offloading read traffic to read replicas, you can distribute the workload across multiple database instances, reducing the load on the primary database and decreasing the number of reads it needs to handle. This helps to improve the overall performance and scalability of your application.
AvsB A:Creating read replicas will ensure the availability of the DB. (CORRECT) B: Will reduce the reading and what happens when there is more reads.
the answer should be A, read replicas enhance high availability by providing failover capabilities in case the primary instance becomes unavailable.
I think A should have been correct if the question had requested for a cost -effective solution because Redis costs money.
Use ElastiCache to reduce reading and ensure high availability. Opt A read replica its for performance not HA I will vote for B
the question is clearly says reduce reads request, so b is the naswer
I think it is B: https://aws.amazon.com/getting-started/hands-on/boosting-mysql-database-performance-with-amazon-elasticache-for-redis/ Although the question just says "RDS Database", it doesn't specify what type of DB.
Options B, C, and D are not directly related to ensuring high availability
why not read replica when you get read performant with HA?
B is not correct. the effectiveness of caching depends on the application. it's not always a good solution.