Metrics analyzed by AWS Compute Optimizer

After you opt in, AWS Compute Optimizer begins analyzing the specifications, such as vCPUs, memory, or storage, and the CloudWatch metrics of your running resources from a period of the last 14 days. If you activate the enhanced infrastructure metrics recommendation preference, AWS Compute Optimizer analyzes for a period that's longer than 14 days. Compute Optimizer requires at least 30 consecutive hours of metrics data from your resource to generate recommendations. The analysis can take up to 12 hours to complete. When the analysis is complete, Compute Optimizer presents its findings on the dashboard page. For more information, see Viewing the AWS Compute Optimizer dashboard.

EC2 instance metrics

Compute Optimizer analyzes the following CloudWatch metrics of your EC2 instances, including instances that are part of Auto Scaling groups.

Metric	Description
CPUUtilization	The percentage of allocated EC2 compute units that are in use on the instance. This metric identifies the processing power that's required to run an application on an instance.
MemoryUtilization	The percentage of memory that's used during the sample period. This metric identifies the memory that's required to run an application on an instance. Memory utilization metrics are analyzed for the following resources: EC2 instances with the CloudWatch agent that's installed on them. For more information, see Enabling memory utilization with the CloudWatch Agent. External EC2 instances from one of the four observability products: Datadog, Dynatrace, Instana, and New Relic. For more information, see Configure external metrics ingestion.
NetworkIn	The number of bytes that's received on all network interfaces by the instance. This metric identifies the volume of incoming network traffic to an instance.
NetworkOut	The number of bytes that are sent out on all network interfaces by the instance. This metric identifies the volume of outgoing network traffic from an instance.
NetworkPacketsIn	The number of packets that are received by the instance.
NetworkPacketsOut	The number of packets that are sent out by the instance.
DiskReadOps	The read operations per second of the instance store volume of the instance.
DiskWriteOps	The write operations per second of the instance store volume of the instance.
DiskReadBytes	The read bytes per second of the instance store volume of the instance.
DiskWriteBytes	The write bytes per second of the instance store volume of the instance.
VolumeReadBytes	The read bytes per second of EBS volumes attached to the instance. Displayed as KiBs in the console.
VolumeWriteBytes	The write bytes per second of EBS volumes attached to the instance. Displayed as KiBs in the console.
VolumeReadOps	The read operations per second of EBS volumes attached to the instance.
VolumeWriteOps	The write operations per second of EBS volumes attached to the instance.

For more information about instance metrics, see List the available CloudWatch metrics for your instances in the Amazon Elastic Compute Cloud User Guide. For more information about EBS volume metrics, see Amazon CloudWatch metrics for Amazon EBS in the Amazon Elastic Compute Cloud User Guide.

Enabling memory utilization with the CloudWatch Agent

To have Compute Optimizer analyze the memory utilization of your instances, install the CloudWatch agent on your instances. Enabling Compute Optimizer to analyze memory utilization data for your instances provides an additional measurement of data that further improves Compute Optimizer's recommendations. For more information about installing the CloudWatch agent, see Collecting Metrics and Logs from Amazon EC2 Instances and On-Premises Servers with the CloudWatch Agent in the Amazon CloudWatch User Guide.

On Linux instances, Compute Optimizer analyses the mem_used_percent metric in the CWAgent namespace, or the legacy MemoryUtilization metric in the System/Linux namespace. On Windows instances, Compute Optimizer analyses the Available MBytes metric in the CWAgent namespace. If both the Available MBytes and Memory % Committed Bytes In Use metrics are configured in the CWAgent namespace, Compute Optimizer chooses Available MBytes as the primary memory metric to generate recommendations.

Note

• We recommend that you configure the CWAgent namespace to use Available MBytes as your memory metric for Windows instances.

• Compute Optimizer also supports the Available KBytes and Available Bytes metrics, and prioritizes both over the Memory % Committed Bytes In Use metric when generating recommendations for Windows instances.

Additionally, the namespace must contain the InstanceId dimension. If the InstanceId dimension is missing or you overwrite it with a custom dimension name, Compute Optimizer can't collect memory utilization data for your instance. Namespaces and dimensions are defined in the CloudWatch Agent configuration file. For more information, see Create the CloudWatch Agent Configuration File in the Amazon CloudWatch User Guide.

Configure external metrics ingestion

You can use the external metrics ingestion feature to configure AWS Compute Optimizer to ingest EC2 memory utilization metrics from one of the four observability products: Datadog, Dynatrace, Instana, and New Relic. When you enable external metrics ingestion, Compute Optimizer analyzes your external EC2 memory utilization metrics in addition to your CPU, disk, network, IO, and throughput data to generate EC2 rightsizing recommendations. These recommendations can provide you with additional savings and enhanced performance. For more information, see External metrics ingestion.

EBS volume metrics

Compute Optimizer analyzes the following CloudWatch metrics of your EBS volumes.

Metric	Description
VolumeReadBytes	The read bytes per second of the EBS volume.
VolumeWriteBytes	The write bytes per second of the EBS volume.
VolumeReadOps	The read operations per second of the EBS volume.
VolumeWriteOps	The write operations per second of the EBS volume.

For more information about these metrics, see Amazon CloudWatch metrics for Amazon EBS in the Amazon Elastic Compute Cloud User Guide.

Lambda function metrics

Compute Optimizer analyzes the following CloudWatch metrics of your Lambda functions.

Metric	Description
Invocations	The number of times your function code is executed, including successful executions and executions that result in a function error.
Duration	The amount of time that your function code spends processing an event.
Errors	The number of invocations that result in a function error. Function errors include exceptions thrown by your code and exceptions thrown by the Lambda runtime. The runtime returns errors for issues such as timeouts and configuration errors.
Throttles	The number of invocation requests that are throttled.

For more information about these metrics, see Working with AWS Lambda function metrics in the AWS Lambda Developer Guide.

In addition to these metrics, Compute Optimizer analyzes the memory utilization of your function during the look-back period. For more information about memory utilization for Lambda functions, see Understanding AWS Lambda behavior using Amazon CloudWatch Logs Insights in the AWS Management & Governance Blog and Using Lambda Insights in CloudWatch in the AWS Lambda Developer Guide.

Metrics for Amazon ECS services on Fargate

Compute Optimizer analyzes the following CloudWatch and Amazon ECS utilization metrics of your Amazon ECS services on Fargate.

Metric	Description
CPUUtilization	The percentage of CPU capacity that's used in the service.
MemoryUtilization	The percentage of memory that's used in the service.

For more information about these metrics, see Amazon ECS CloudWatch metrics in the Amazon ECS User Guide for AWS Fargate.