Why might you want to allow extra time for setting up the database in an anomaly-based system?

Q: What can I measure with Amazon CloudWatch Metrics?

Amazon CloudWatch allows you to monitor AWS cloud resources and the applications you run on AWS. Metrics are provided automatically for a number of AWS products and services, including Amazon EC2 instances, EBS volumes, Elastic Load Balancers, Auto Scaling groups, EMR job flows, RDS DB instances, DynamoDB tables, ElastiCache clusters, RedShift clusters, OpsWorks stacks, Route 53 health checks, SNS topics, SQS queues, SWF workflows, and Storage Gateways. You can also monitor custom metrics generated by your own applications and services.

Q: What is the retention period of all metrics?

You can publish and store custom metrics down to one-second resolution. Extended retention of metrics was launched on November 1, 2016, and enabled storage of all metrics for customers from the previous 14 days to 15 months. CloudWatch retains metric data as follows:

• Data points with a period of less than 60 seconds are available for 3 hours. These data points are high-resolution custom metrics.
• Data points with a period of 60 seconds (1 minute) are available for 15 days
• Data points with a period of 300 seconds (5 minute) are available for 63 days 
• Data points with a period of 3600 seconds (1 hour) are available for 455 days (15 months)

Data points that are initially published with a shorter period are aggregated together for long-term storage. For example, if you collect data using a period of 1 minute, the data remains available for 15 days with 1-minute resolution. After 15 days this data is still available, but is aggregated and is retrievable only with a resolution of 5 minutes. After 63 days, the data is further aggregated and is available with a resolution of 1 hour. If you need availability of metrics longer than these periods, you can use the GetMetricStatistics API to retrieve the datapoints for offline or different storage.

The feature is currently available in US East (N. Virginia), US West (Oregon), US West (N. California), EU (Ireland), EU (Frankfurt), S. America (São Paulo), Asia Pacific (Singapore), Asia Pacific (Tokyo), Asia Pacific (Seoul), Asia Pacific (Mumbai), Asia Pacific (Sydney), EU (London), Canada (Central), US East (Ohio), and China (Beijing).

Q: What is the minimum resolution for the data that Amazon CloudWatch receives and aggregates?

The minimum resolution supported by CloudWatch is one-second data points, which is a high-resolution metric, or you can store metrics at one-minute granularity. Sometimes metrics are received by Cloudwatch at varying intervals, such as three-minute or five-minute intervals. If you do not specify that a metric is high resolution, by setting the StorageResolution field in the PutMetricData API request, then by default CloudWatch will aggregate and store the metrics at one-minute resolution.

Depending on the age of data requested, metrics will be available at the resolutions defined in the retention schedules above. For example, if you request for one-minute data for a day from 10 days ago, you will receive the 1440 data points. However, if you request for one-minute data from five months back, the UI will automatically change the granularity to one-hour and the GetMetricStatistics API will not return any output.

Q: Can I delete any metrics?

CloudWatch does not support metric deletion. Metrics expire based on the retention schedules described above.

Q: Will I lose the metrics data if I disable monitoring for an Amazon EC2 instance?

No. You can always retrieve metrics data for any Amazon EC2 instance based on the retention schedules described above. However, the CloudWatch console limits the search of metrics to two weeks after a metric is last ingested to ensure that the most up-to-date instances are shown in your namespace.

Q: Can I access the metrics data for a terminated Amazon EC2 instance or a deleted Elastic Load Balancer?

Yes. Amazon CloudWatch stores metrics for terminated Amazon EC2 instances or deleted Elastic Load Balancers for 15 months.

Q: Why does the graphing of the same time window look different when I view the metrics in five-minute and one-minute periods?

If you view the same time window in a 5 minute period versus a 1 minute period, you may see that data points are displayed in different places on the graph. For the period you specify in your graph, Amazon CloudWatch will find all the available data points and calculates a single, aggregate point to represent the entire period. In the case of a 5 minute period, the single data point is placed at the beginning of the 5 minute time window. In the case of a 1 minute period, the single data point is placed at the 1 minute mark. We recommend using a one minute period for troubleshooting and other activities that require the most precise graphing of time periods.

Q: What is a Custom Metric?

You can use Amazon CloudWatch to monitor data produced by your own applications, scripts, and services. A custom metric is any metric you provide to Amazon CloudWatch. For example, you can use custom metrics as a way to monitor the time to load a web page, request error rates, number of processes or threads on your instance, or amount of work performed by your application. You can get started with custom metrics by using the PutMetricData API, our sample monitoring scripts for Windows and Linux, CloudWatch collectd plugin, as well as a number of applications and tools offered by AWS partners.

Q: What resolution can I get from a Custom Metric?

A custom metric can be one of the following:

• Standard resolution, with data having one-minute granularity
• High resolution, with data at a granularity of one second

By default, metrics are stored at one-minute resolution in CloudWatch. You can define a metric as high-resolution by setting the StorageResolution parameter to one in the PutMetricData API request. If you do not set the optional StorageResolution parameter, then CloudWatch will default to storing the metrics at one-minute resolution.

When you publish a high-resolution metric, CloudWatch stores it with a resolution of one second, and you can read and retrieve it with a period of one second, five seconds, 10 seconds, 30 seconds, or any multiple of 60 seconds.

Custom metrics follow the same retention schedule listed above.

Q: What metrics are available at high resolution?

Currently, only custom metrics that you publish to CloudWatch are available at high resolution. High-resolution custom metrics are stored in CloudWatch at one-second resolution. High resolution is defined by the StorageResolution parameter in the PutMetricData API request, with a value of one, and is not a required field. If you do not specify a value for the optional StorageResolution field, then CloudWatch will store the custom metric at one-minute resolution by default.

Q: Are high-resolution custom metrics priced differently than regular custom metrics?

No, high-resolution custom metrics are priced in the same manner as standard one-minute custom metrics.

Q: When would I use a Custom Metric over having my program emit a log to CloudWatch Logs?

You can monitor your own data using custom metrics, CloudWatch Logs, or both. You may want to use custom metrics if your data is not already produced in log format, for example operating system processes or performance measurements. Or, you may want to write your own application or script, or one provided by an AWS partner. If you want to store and save individual measurements along with additional detail, you may want to use CloudWatch Logs.

Q: What statistics can I view and graph in CloudWatch?

You can retrieve, graph, and set alarms on the following statistical values for Amazon CloudWatch metrics: Average, Sum, Minimum, Maximum, and Sample Count. Statistics can be computed for any time periods between 60 seconds and one day. For high-resolution custom metrics, statistics can be computed for time periods between one second and three hours.

Q: What is CloudWatch Application Insights for .NET and SQL Server?

Amazon CloudWatch Application Insights for .NET and SQL Server is a capability that you can use to easily monitor your .NET and SQL Server applications. It helps identify and set up key metrics and logs across your application resources and technology stack, i.e. database, web (IIS) and application servers, OS, load balancers, queues, etc. It constantly monitors these telemetry data to detect and correlate anomalies and errors, to notify you of any problems in your application. To aid in troubleshooting, it creates automatic dashboards to visualize problems it detects which includes correlated metric anomalies and log errors, along with additional insights to point you to their potential root cause.

Q: What are the benefits of using CloudWatch Application Insights for .NET and SQL Server?

• Automatically recognize application metrics and logs: It scans your application resources, provides a list of recommended metrics and logs to monitor, and sets them up automatically, making it easier to set up monitoring for your applications. 
• Intelligent problem detection: It uses built-in rules and machine learning algorithms to dynamically monitor and analyze symptoms of a problem across your application stack and detect application problems. It helps you reduce the overhead of dealing with individual metric spikes, or events, or log exceptions, and instead get notified on real problems, along with contextual information these problems.
• Faster troubleshooting: It assesses the detected problems to give you insights on them, such as the possible root cause of the detected problem and list of metrics and logs impacted because of the problem. You can provide feedback on generated insights to make the problem detection engine specific to your use case.
  

Q: How do I get started with monitoring using CloudWatch Application Insights for .NET and SQL Server?

On-board application: Specify the application you want to monitor by choosing the AWS Resource Group associated with it.

Identify application components: It analyzes your application resources to identify application components (standalone resources, or groups of related resources such as auto scaling groups and load balancer groups). You can also customize components by grouping resources for better insights and easy onboarding.

Enable monitoring: For your application components, you can specify the technology tier i.e. IIS front-end, .NET worker tier, etc. Based on your selection it provides a recommended set of metrics and logs that can be customized based on your needs. Once you save these “monitors”, Application Insights for .NET and SQL Server sets up CloudWatch to collect these on your behalf.

Once onboarded, Application Insights for .NET and SQL Server uses a combination of pre-built rules and machine learning models to start identifying application problems. It creates automated dashboards on CloudWatch with the list of problems detected, and a detailed view for these problems along with related anomalies and errors.

Q: What is CloudWatch Metric Streams?

CloudWatch Metric Streams is a feature that enables you to continuously stream CloudWatch metrics to a destination of your choice with minimal setup and configuration. It is a fully managed solution, and doesn’t require you to write any code or maintain any infrastructure. With a few clicks, you can configure a metric stream to destinations like Amazon Simple Storage Service (S3). You can also send your metrics to a selection of third-party service providers to keep your operational dashboards up to date.

Q: Why should I use CloudWatch Metric Streams?

Metric Streams provides an alternative way of obtaining metrics data from CloudWatch without the need to poll APIs. You can create a metric stream with just a few clicks, and your metrics data will start to flow to your destination. You can easily direct your metrics to your data lake on AWS such as on Amazon S3, and start analyzing usage or performance with tools such as Amazon Athena. Metrics Streams also makes it easier to send CloudWatch metrics to popular third-party service providers using an Amazon Kinesis Data Firehose HTTP endpoint. You can create a continuous, scalable stream including the most up-to-date CloudWatch metrics data to power dashboards, alarms, and other tools that rely on accurate and timely metric data.

Q: How can I create and manage CloudWatch Metric Streams?

You can create and manage Metric Streams through the CloudWatch Console or programmatically through the CloudWatch API, AWS SDK, AWS CLI, or AWS CloudFormation to provision and configure Metric Streams. You can also use AWS CloudFormation templates provided by third-party service providers to set up Metric Streams delivery to destinations outside AWS. For more information, see the documentation on CloudWatch Metric Streams.

Q: Can I manage metrics to be included in my CloudWatch Metric Stream?

Yes. It is possible to choose to send all metrics by default, or create filter rules to include and exclude groups of metrics defined by namespace, e.g. AWS/EC2. Metric Streams automatically detects new metrics matching filter rules and includes metric updates in the stream. When resources are terminated, Metric Streams will automatically stop sending updates for the inactive metrics.

Q: What formats does CloudWatch Metric Streams support?

Metric Streams can output in either OpenTelemetry or JSON format. You can select the output format when creating or managing metric streams.

Q: Can I monitor the cost and volume of data delivered by CloudWatch Metric Streams?

Yes. You can visit the monitoring section of the Metric Streams console page. You will see automatic dashboards for the volume of metric updates over time. These metrics are also available under the AWS/CloudWatch namespace and can be used to create alarms to send notifications in the case of an unusual spike in volume.