Question 271 - DBS-C01 discussion

Explanation from Amazon documents:AWS Database Migration Service (AWS DMS) is a service that helps you migrate data from one data source to another. AWS DMS supports full load and change data capture (CDC) modes, which enable you to migrate data with minimal downtime. AWS DMS also supports parallel load, which allows you to load data from multiple tables or partitions concurrently.To improve database performance, reduce data migration time, and create multiple DMS tasks, the database specialist should use the following combination of changes:Use a smaller set of tables with each DMS task. Set the MaxFullLoadSubTasks parameter to a higher value. This change will allow the database specialist to split the migration workload into smaller and more manageable units, and increase the parallelism of the full load process. The MaxFullLoadSubTasks parameter specifies the maximum number of tables that are loaded in parallel for each DMS task. By setting this parameter to a higher value, the database specialist can increase the throughput and performance of the full load process.Use parallel load with different data boundaries for larger tables. This change will allow the database specialist to divide the larger tables into smaller chunks based on a partition key or a range of values, and load them in parallel using multiple DMS tasks. Parallel load can significantly reduce the migration time and improve the performance of large tables.Therefore, option B and D are the correct combination of changes to meet the requirements. Option A is incorrect because increasing the value of the ParallelLoadThreads parameter in the DMS task settings for the tables will not improve the performance or reduce the migration time significantly. The ParallelLoadThreads parameter specifies the number of threads that are used to load data from a single table or partition. By increasing this parameter, the database specialist may increase the CPU utilization and network bandwidth consumption of the source and target databases, but not the parallelism of the full load process. Option C is incorrect because using a smaller set of tables with each DMS task and setting the MaxFullLoadSubTasks parameter to a lower value will decrease the parallelism and performance of the full load process. Option E is incorrect because running the DMS tasks on a larger instance class and increasing local storage on the instance will not address the root cause of the performance issue, which is the lack of parallelism and partitioning of the large tables.