An application uses a DynamoDB table to store data with each record being 6KB in size.
The application needs to perform 100 eventually consistent read operations per second and 40 write operations per second.
What is the provisioned RCU value required to meet these requirements?
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A. B. C. D.Answer: D.
Option D is CORRECT.
1RCU is equivalent to two strongly consistent reads per second of an item up to 4KB in size.
Thus, to calculate the required RCU in this scenario, we need to:
1
Round up the item size to the nearest 4KB (8KB)
2
Divide by 4KB to calculate the number of read units (8/4 = 2)
3
Divide by 2 to calculate the number of eventually consistent read units per item (2/2 = 1)
4
Multiple by operations per second to get the total RCU required (1*100 = 100 RCU)
Reference:
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/HowItWorks.ReadWriteCapacityMode.html#HowItWorks.ProvisionedThroughput.ManualTo determine the provisioned RCU value required to meet the given requirements, we need to calculate the total number of read and write capacity units (RCUs and WCUs, respectively) needed for the DynamoDB table.
The first step is to determine the total number of RCUs required for the read operations. Each read operation consumes 1 RCU for an item of size up to 4 KB. Since each item in the table is 6 KB in size, each read operation will consume 2 RCUs. Therefore, 100 eventually consistent read operations per second will consume 200 RCUs (100 * 2).
The next step is to determine the total number of WCUs required for the write operations. Each write operation consumes 1 WCU for an item of size up to 1 KB. Since each item in the table is 6 KB in size, each write operation will consume 6 WCUs. Therefore, 40 write operations per second will consume 240 WCUs (40 * 6).
To determine the total provisioned RCU value required for the table, we need to take the maximum of the total RCUs and WCUs calculated above. In this case, the maximum value is 240, which means that we need to provision 240 RCUs for the DynamoDB table.
Therefore, the correct answer is option B: 600 RCU. Since the provisioned RCU is the smallest increment of RCUs that can be provisioned, we need to round up the required value of 240 to the next multiple of 4, which is 600.