How to Solve Insufficient Memory Allocation Issue in ElastiCache

Answer: D.

Options A and B are incorrect because the configuration parameters of an ElastiCache cluster must be modified using custom parameter groups.

Option C is incorrect because it is recommended to use the reserved-memory-percent parameter.

Each node in a cluster can be of a different type.

This means that each node can have a different maximum memory.

Therefore, using the reserved-memory parameter would require a different value for this parameter for each node depending on the node's type and maximum memory.

In turn, this requires the creation of a separate custom parameter group for each node type.

To simplify the operation of clusters with various node types, you can use the reserved-memory-percent parameter.

In this way, one parameter can be configured, and one parameter group can be used to manage the cluster's reserved memory, regardless of the node types comprising the cluster.

Therefore, option D is CORRECT.

Reference:

https://docs.aws.amazon.com/AmazonElastiCache/latest/red-ug/redis-memory-management.html

The correct answer is B. Using AWS elasticache modify-cache-cluster CLI command, set the reserved-memory-percent parameter to 50.

Explanation: ElastiCache is a managed caching service provided by AWS that is commonly used to improve the performance of web applications by caching frequently accessed data in memory. When an ElastiCache cluster is created, a certain amount of memory is reserved for non-data use, such as overhead and system processes.

If the ElastiCache cluster does not have enough memory allocated for non-data use, it can lead to performance issues. To solve this issue, the database specialist needs to increase the amount of memory reserved for non-data use.

The reserved-memory-percent parameter determines the percentage of memory that is reserved for non-data use. By default, this value is set to 50%. The specialist can use the AWS elasticache modify-cache-cluster CLI command to increase the percentage of memory that is reserved for non-data use.

Option A, creating a custom parameter group with the reserved-memory parameters set to 50, is not the correct solution because the reserved-memory parameter is not a valid parameter for ElastiCache.

Option C, creating a custom parameter group with the reserved-memory parameters set to 50 and applying the custom parameter group to the cluster, is also not the correct solution because the reserved-memory parameter is not a valid parameter for ElastiCache.

Option D, creating a custom parameter group with the reserved-memory-percent parameter set to 50 and applying the custom parameter group to the cluster, is similar to the correct answer but not as efficient because it involves creating a custom parameter group when the same result can be achieved using the modify-cache-cluster command directly.