Identify any Amazon RDS database instances that appear to be underutilized and downsize (resize) them to help lower the cost of your monthly AWS bill. By default, an RDS database instance is considered "underutilized" when meets the following criteria:
- The average CPU utilization has been less than 60% for the last 7 days.
- The total number of ReadIOPS and WriteIOPS recorded per day for the last 7 days has been less than 100 on average.
The AWS CloudWatch metrics utilized to detect underused RDS instances are:
- CPUUtilization - the percentage of CPU utilization (Units: Percent).
- ReadIOPS and WriteIOPS - the average number of disk I/O (Input/Output) operations per second (Units: Count/Second).
Note: You can change the default threshold values for this rule on the Cloud Conformity console and set your own values for CPU utilization, and the total number of ReadIOPS and WriteIOPS to configure the underuse level for your RDS instances.
This rule can help you work with the AWS Well-Architected Framework
This rule resolution is part of the Cloud Conformity Security & Compliance tool for AWS
Downsizing underused RDS database instances represents a good strategy for optimizing your monthly AWS costs. For example, downgrading a db.m3.large RDS MySQL database instance to a db.m3.medium instance due to CPU and IOPS underuse, you can save roughly $70 per month (as of March 2017).
To identify any underutilized RDS instances provisioned within your AWS account, perform the following actions:
Remediation / Resolution
Option 1: Downsize (resize) the underused RDS instances provisioned within your AWS account. To resize any RDS database instance that is currently running in "underutilized" mode, perform the following actions:(!) Important note: the following process assumes that the RDS database instances selected for downsize are NOT currently used in production or for critical operations. To resize production instances without any downtime, you should create a full snapshot of your current instance and use it to launch a new database instance with the required type.
Option 2: Suppress the rule check. If the selected underused RDS database instance configuration must remain unchanged (some workload scenarios can result in low resource utilization by design), you should turn off the conformity rule check for the specified instance from the Cloud Conformity console.
- AWS Documentation
- Trusted Advisor Best Practices (Checks)
- Amazon RDS Metrics and Dimensions
- DB Instance Class
- Modifying an Amazon RDS DB Instance and Using the Apply Immediately Parameter
- SIMPLE MONTHLY CALCULATOR
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You are auditing:
Underutilized RDS Instance
Risk level: High