Azure Monitor Metrics overview
Azure Monitor Metrics is a feature of Azure Monitor that collects numeric data from monitored resources into a time-series database. Metrics are numerical values that are collected at regular intervals and describe some aspect of a system at a particular time.
Metrics in Azure Monitor are lightweight and capable of supporting near-real-time scenarios. For these reasons, they're useful for alerting and fast detection of issues. You can:
- Analyze them interactively by using Metrics Explorer.
- Be proactively notified with an alert when a value crosses a threshold.
- Visualize them in a workbook or dashboard.
Note
Azure Monitor Metrics is one half of the data platform that supports Azure Monitor. The other half is Azure Monitor Logs, which collects and organizes log and performance data. You can analyze that data by using a rich query language.
The Azure Monitor Metrics feature can only store numeric data in a particular structure. The Azure Monitor Logs feature can store a variety of datatypes, each with its own structure. You can also perform complex analysis on log data by using log queries, which you can't use for analysis of metric data.
What can you do with Azure Monitor Metrics?
The following table lists the ways that you can use the Azure Monitor Metrics feature.
| Uses | Description |
|---|---|
| Analyze | Use Metrics Explorer to analyze collected metrics on a chart and compare metrics from various resources. |
| Alert | Configure a metric alert rule that sends a notification or takes automated action when the metric value crosses a threshold. |
| Visualize | Pin a chart from Metrics Explorer to an Azure dashboard. Create a workbook to combine with multiple sets of data in an interactive report. |
| Automate | Use Autoscale to increase or decrease resources based on a metric value crossing a threshold. |
| Retrieve | Access metric values from a:
|
| Export | Route metrics to logs to analyze data in Azure Monitor Metrics together with data in Azure Monitor Logs and to store metric values for longer than 93 days. Stream metrics to an event hub to route them to external systems. |
| Archive | Archive the performance or health history of your resource for compliance, auditing, or offline reporting purposes. |
Data collection
Azure Monitor collects metrics from the following sources. After these metrics are collected in the Azure Monitor metric database, they can be evaluated together regardless of their source:
- Azure resources: Platform metrics are created by Azure resources and give you visibility into their health and performance. Each type of resource creates a distinct set of metrics without any configuration required. Platform metrics are collected from Azure resources at one-minute frequency unless specified otherwise in the metric's definition.
- Applications: Application Insights creates metrics for your monitored applications to help you detect performance issues and track trends in how your application is being used. Values include Server response time and Browser exceptions.
- Virtual machine agents: Metrics are collected from the guest operating system of a virtual machine. You can enable guest OS metrics for Windows virtual machines by using the Windows diagnostic extension and for Linux virtual machines by using the InfluxData Telegraf agent.
For a complete list of data sources that can send data to Azure Monitor Metrics, see What is monitored by Azure Monitor?.
Security
All communication between connected systems and the Azure Monitor service is encrypted using the TLS 1.2 (HTTPS) protocol. The Microsoft SDL process is followed to ensure all Azure services are up-to-date with the most recent advances in cryptographic protocols.
Secure connection is established between the agent and the Azure Monitor service using certificate-based authentication and TLS with port 443. Azure Monitor uses a secret store to generate and maintain keys. Private keys are rotated every 90 days and are stored in Azure and are managed by the Azure operations who follow strict regulatory and compliance practices. For more information on security, see Encryption of data in transit, Encryption of data at rest, and Azure Monitor Logs data security
Metrics Explorer
Use Metrics Explorer to interactively analyze the data in your metric database and chart the values of multiple metrics over time. You can pin the charts to a dashboard to view them with other visualizations. You can also retrieve metrics by using the Azure monitoring REST API.
For more information, see Getting started with Azure Monitor Metrics Explorer.
Data structure
Data that Azure Monitor Metrics collects, is stored in a time-series database that's optimized for analyzing time-stamped data. Each set of metric values is a time series with the following properties:
- The time when the value was collected.
- The resource that the value is associated with.
- A namespace that acts like a category for the metric.
- A metric name.
- The value itself.
- Multiple dimensions when they're present. Custom metrics are limited to 10 dimensions.
Multi-dimensional metrics
One of the challenges to metric data is that it often has limited information to provide context for collected values. Azure Monitor addresses this challenge with multi-dimensional metrics.
Metric dimensions are name/value pairs that carry more data to describe the metric value. For example, a metric called Available disk space might have a dimension called Drive with values C: and D:. That dimension would allow viewing available disk space across all drives or for each drive individually.
See Apply dimension filters and splitting for details on viewing metric dimensions in metrics explorer.
Nondimensional metric
The following table shows sample data from a nondimensional metric, network throughput. It can only answer a basic question like "What was my network throughput at a given time?"
| Timestamp | Metric value |
|---|---|
| 8/9/2017 8:14 | 1,331.8 Kbps |
| 8/9/2017 8:15 | 1,141.4 Kbps |
| 8/9/2017 8:16 | 1,110.2 Kbps |
Network throughput and two dimensions ("IP" and "Direction")
The following table shows sample data from a multidimensional metric, network throughput with two dimensions called IP and Direction. It can answer questions such as "What was the network throughput for each IP address?" and "How much data was sent versus received?"
| Timestamp | Dimension "IP" | Dimension "Direction" | Metric value |
|---|---|---|---|
| 8/9/2017 8:14 | IP="192.168.5.2" | Direction="Send" | 646.5 Kbps |
| 8/9/2017 8:14 | IP="192.168.5.2" | Direction="Receive" | 420.1 Kbps |
| 8/9/2017 8:14 | IP="10.24.2.15" | Direction="Send" | 150.0 Kbps |
| 8/9/2017 8:14 | IP="10.24.2.15" | Direction="Receive" | 115.2 Kbps |
| 8/9/2017 8:15 | IP="192.168.5.2" | Direction="Send" | 515.2 Kbps |
| 8/9/2017 8:15 | IP="192.168.5.2" | Direction="Receive" | 371.1 Kbps |
| 8/9/2017 8:15 | IP="10.24.2.15" | Direction="Send" | 155.0 Kbps |
| 8/9/2017 8:15 | IP="10.24.2.15" | Direction="Receive" | 100.1 Kbps |
Note
Dimension names and dimension values are case-insenstive.
Retention of metrics
Platform metrics
Platform metrics are stored for 93 days with the following exceptions:
Classic guest OS metrics: These performance counters are collected by the Windows diagnostic extension or the Linux diagnostic extension and routed to an Azure Storage account. Retention for these metrics is guaranteed to be at least 14 days, although no expiration date is written to the storage account.
For performance reasons, the portal limits how much data it displays based on volume. So, the actual number of days that the portal retrieves can be longer than 14 days if the volume of data being written isn't large.
Guest OS metrics sent to Azure Monitor Metrics: These performance counters are collected by the Windows diagnostic extension and sent to the Azure Monitor data sink, or the InfluxData Telegraf agent on Linux machines, or the newer Azure Monitor agent via data-collection rules. Retention for these metrics is 93 days.
Guest OS metrics collected by the Log Analytics agent: These performance counters are collected by the Log Analytics agent and sent to a Log Analytics workspace. Retention for these metrics is 31 days and can be extended up to 2 years.
Application Insights log-based metrics: Behind the scenes, log-based metrics translate into log queries. Their retention is variable and matches the retention of events in underlying logs, which is 31 days to 2 years. For Application Insights resources, logs are stored for 90 days.
Note
You can send platform metrics for Azure Monitor resources to a Log Analytics workspace for long-term trending.
While platform metrics are stored for 93 days, you can only query (in the Metrics tile) for a maximum of 30 days' worth of data on any single chart. This limitation doesn't apply to log-based metrics. If you see a blank chart or your chart displays only part of metric data, verify that the difference between start and end dates in the time picker doesn't exceed the 30-day interval. After you've selected a 30-day interval, you can pan the chart to view the full retention window.
Next steps
- Learn more about the Azure Monitor data platform.
- Learn about log data in Azure Monitor.
- Learn about the monitoring data available for various resources in Azure.