How does the Topic Score Threshold in the Instance Rightsizing Policy work?

Products

• CloudHealth

Issue/Introduction

Consider these threshold specifications for the CPU utilization of an instance.

This is how actual CPU utilization maps to the metric score in this example. If theaverage CPU usage is 50%, the corresponding score is 67. If the average CPU usage increases to 75%, it would be 50% through the usage range (51% to 100% average CPU usage), and it therefore maps to 50% of the score range, or 84.

In addition to the thresholds that correlate with score values, you can also change the weight of each topic score.

By default, the Total Score is distributed evenly across CPU, Memory, Disk, Network In, and Network Out, with each metric contributing 20%. The Total Score is calculated as follows:

Total Score = f (CPU, Memory, Disk, Network In, Network Out) Here, f is the weighted average

By changing the weight, including lowering a weight to 0, you can make the Total Score become more reflective of your organizational requirements. The weighted score is calculated as follows:

Weighted Score = (Weight/Sum of weights) * Score

Therefore, if you assign CPU a weight of 2, and assign Memory, Disk, Network In, and Network Out each a weight of 1, the weighted score for each topic is calculated as follows:

Weighted CPU Score = (2/6) * Score Weighted Memory Score = (1/6) * Score Weighted Disk Score = (1/6) * Score Weighted Network In Score = (1/6) * Score Weighted Network Out Score = (1/6) * Score

The sum of these weighted scores is the Total Score for the instance.