Sampling Rate Calculation for AWS X-Ray Sampling Rule

Correct Answer - A.

Let us suppose that we specify a value for Reservoir Rate as 60 and Fixed Rate as 20

Now, if your application receives 200 requests in a second, then the total number of requests that would be traced or sampled will be: -

"Reservoir Rate" + Fixed Rate % [(Total Requests - Reservoir Rate)]

- 60 + (200-60) * 20%

- 60 + (140) * 20%

- 60 + 28

- 88

Option B, C, & D are incorrect as these values are not matching the reservoir size & fixed-rate sampling rate.

For more information on Configuring Sampling Rules in the AWS X-Ray Console, refer to the following URL-

https://docs.aws.amazon.com/xray/latest/devguide/xray-api-sampling.html

AWS X-Ray is a service that enables developers to analyze and debug production, distributed applications, such as microservices or serverless applications. It helps to identify issues and opportunities for optimization by providing trace information of requests as they travel through your application.

When you configure a sampling rule in AWS X-Ray, you can control the percentage of requests that are traced for analysis. Sampling helps to reduce the volume of data that needs to be processed and stored while still providing a representative sample of your application's traffic.

In this question, the sampling rule is configured with a reservoir size of 60 and a fixed rate of 20%. The reservoir size refers to the number of traces that can be stored at a given time. The fixed rate refers to the percentage of requests that will be traced for analysis.

The question states that there are 200 requests per second matching the rule defined. To calculate how many requests will be sampled per second, we need to use the following formula:

sampled requests per second = (fixed rate * requests per second) / reservoir size

Substituting the values given in the question, we get:

sampled requests per second = (20% * 200) / 60 sampled requests per second = (0.2 * 200) / 60 sampled requests per second = 40 / 60 sampled requests per second = 0.67

Therefore, the answer is C. 40 requests per second.