Oracle Cloud Infrastructure Documentation

Overview of Monitoring

Use the Oracle Cloud Infrastructure Monitoring service to actively and passively monitor cloud resources using the Metrics and Alarms features. Learn how Monitoring works.

This image shows metrics and alarms as used in the Monitoring service.

Tip

Watch a video introduction to the service.

How Monitoring Works

The Monitoring service uses metrics  to monitor resources and alarms  to notify you when these metrics meet alarm-specified triggers.

Metrics are emitted to the Monitoring service as raw data points , or timestamp-value pairs, along with dimensions  and metadata. Metrics come from various sources:

You can transfer metrics from the Monitoring service using Connector Hub. For more information, see Creating a Connector with a Monitoring Source.

Metric data posted to the Monitoring service is only presented to you or consumed by the Oracle Cloud Infrastructure features that you enable to use metric data.

When you query a metric, the Monitoring service returns aggregated data according to the specified parameters. You can specify a range (such as the last 24 hours), statistic , and interval . The Console displays one monitoring chart per metric for selected resources. The aggregated data in each chart reflects the selected statistic and interval. API requests can optionally filter by dimension  and specify a resolution . API responses include the metric name along with its source compartment and metric namespace . You can feed the aggregated data into a visualization or graphing library.

Metric and alarm data is accessible from the Console, CLI, and API. For retention periods, see Storage Limits.

The Alarms feature of the Monitoring service publishes alarm messages  to configured destinations, such as topics in Notifications and streams in Streaming.

Metrics Feature Overview

The Metrics feature relays metric data about the health, capacity, and performance of cloud resources.

A metric is a measurement related to health, capacity, or performance of a resource . Resources, services, and applications emit metrics to the Monitoring service. Common metrics reflect data related to:

  • Availability and latency
  • Application uptime and downtime
  • Completed transactions
  • Failed and successful operations
  • Key performance indicators (KPIs), such as sales and engagement quantifiers

By querying Monitoring for this data, you can understand how well the systems and processes are working to achieve the service levels you commit to your customers. For example, you can monitor the CPU utilization and disk reads of compute instances . You can then use this data to decide when to provision more instances to handle increased load, troubleshoot issues with the instance, or better understand system behavior.

Example Metric: Failure Rate

For application health, one of the common KPIs is failure rate, for which a common definition is the number of failed transactions divided by total transactions. This KPI is typically delivered through application monitoring and management software.

As a developer, you can capture this KPI from applications using custom metrics. Record observations every time an application transaction takes place and then post that data to the Monitoring service. In this case, set up metrics to capture failed transactions, successful transactions, and transaction latency (time spent per completed transaction).

Alarms Feature Overview

Use alarms to monitor the health, capacity, and performance of cloud resources.

Resources emit metric data points to Monitoring. When triggered, alarms send messages to the configured destination. For Notifications, messages are sent to subscriptions in the configured topic. For Streaming, messages are sent to the configured stream).

The Alarms feature of the Monitoring service works with the configured destination service to notify you when metrics meet alarm-specified triggers. The previous illustration depicts the flow, starting with resources emitting metric data points to Monitoring. When triggered, an alarm  sends an alarm message to the configured destination. For Notifications, messages are sent to subscriptions  in the configured topic. For Streaming, messages are sent to the configured stream. (This illustration doesn't cover raw and aggregated metric data. For these details, see the "Monitoring Overview" illustration at the top of this page.)

When configured, repeat notifications remind you of a continued firing state at the configured repeat interval. You're also notified when an alarm transitions back to the OK state, or when an alarm is reset.

Alarm Evaluations

Monitoring evaluates alarms once per minute to find alarm status.

When the alarm splits notifications, Monitoring evaluates each tracked metric stream. If the evaluation of that metric stream indicates a new FIRING status or other qualifying event, then Monitoring sends an alarm message.

Monitoring tracks metric streams per alarm for qualifying events, but messages are subject to the destination service limits.

Illustration of Alarm Evaluation

Consider an alarm that measures the 90th percentile of the metric CpuUtilization.

{
  "compartmentId": "ocid1.compartment.oc1..exampleuniqueID",
  "destinations": ["ocid1.onstopic.exampleuniqueID"],
  "displayName": "High CPU Utilization",
  "id": "ocid1.alarm.oc1..exampleuniqueID",
  "lifecycleState": "ACTIVE",
  "metricCompartmentId": "ocid1.compartment.oc1..exampleuniqueID",
  "namespace": "oci_computeagent",
  "pendingDuration": "PT3M",
  "query": "CpuUtilization[1m]{availabilityDomain = \"cumS:PHX-AD-1\"}.groupBy(availabilityDomain).percentile(0.9) > 85",
  "repeatNotificationDuration": "PT2H",
  "severity": "WARNING",
  "isEnabled": true,
  "timeCreated": "2023-02-01T01:02:29.600Z",
  "timeUpdated": "2023-02-03T01:02:29.600Z"
}

Notes about this example alarm:

  • The percentile is specified in the query as the statistic (bold):
    CpuUtilization[1m]{availabilityDomain = \"cumS:PHX-AD-1\"}.groupBy(availabilityDomain).percentile(0.9) > 85
  • Each data point is the 90th percentile (percentile(0.9)) of a one-minute window, specified in the query as the interval (bold):
    CpuUtilization[1m]{availabilityDomain = \"cumS:PHX-AD-1\"}.groupBy(availabilityDomain).percentile(0.9) > 85
  • Data point values for this statistic could be anything from null (absent) to 100.
  • Data point evaluations:
    • For any data point value greater than 85, the evaluation is true (1). A true evaluation means that the trigger rule condition has been met.
    • For any data point value that isn't greater than 85, the evaluation is false (0).
  • The alarm doesn't fire until the trigger rule condition is met for three successive minutes. This configuration is the alarm's trigger delay (pendingDuration), set as PT3M.
  • The alarm updates its state to OK when the breaching condition has been clear for the most recent minute.

The following image shows an aggregated metric stream for the example alarm. Each data point is indicated by a square.


Aggregated metric stream for the example alarm.

The following table shows consecutive alarm evaluations for the example alarm. The alarm is evaluated on a moving window of three one-minute intervals.

Evaluation period timestamp Minutes in period Data point evaluations* Status
3 [1, 2, 3] [0, 0, 0] OK
4 [2, 3, 4] [0, 0, 1] OK
5 [3, 4, 5] [0, 1, 1] OK
6 [4, 5, 6] [1, 1, 1] FIRING
7 [5, 6, 7] [1, 1, 1] FIRING
8 [6, 7, 8] [1, 1, 0] OK
9 [7, 8, 9] [1, 0, 0] OK
10 [8, 9, 10] [0, 0, 0] OK

*A value of one (1) means that the trigger rule condition is met.

About the Number of Metric Stream Data Points for an Alarm

The number of metric stream data points for an alarm is determined by the number of query streams and minutes analyzed.

  • The number of query streams depends on the metric streams returned by the alarm query.
  • The minutes analyzed depends on the alarm attributes interval, resolution, and pendingDuration. For alarm queries, the only valid value for resolution is 1m. For more information about interval, see Interval. For more information about resolution and pendingDuration, see Monitoring API.

Each alarm gets evaluated once every minute, and thus each alarm is evaluated 1440 times per day. Each evaluation queries the data in the time window defined by interval and it checks the period of time that the alarm persists defined by pendingDuration. Therefore, minutes analyzed at every minute is calculated by the following expression:

minutes analyzed at every minute = interval * ceiling(pendingDuration / resolution)

About the Internal Reset Period

The internal reset period determines when an alarm stops checking for an absent metric that triggered the Firing state in the previous evaluation. When the metric is absent for the entire period, later alarm evaluations ignore the indicated metric stream. If no other metric streams are causing the Firing state for the alarm, then the alarm transitions to OK and sends a RESET message. By default, the RESET message arrives after 13 minutes (internal reset period plus the default slack period of 3 minutes). You can customize the slack period.

The length of the internal reset period is globally configured at 10 minutes, which causes the alarm history to show a 10-minute difference.

The beginning of an internal reset period depends on the alarm type. For threshold alarms, the internal reset period starts when the first absence is detected. For absence alarms, the internal reset period starts after completion of the absence detection period (default of 2 hours, can be customized).

Data Points Gathered During an Internal Reset Period

Each evaluation during the ten-minute internal reset period accounts for all data points in that period.

For example, consider a metric stream (A) that exceeds the threshold (dashed red line in following diagrams). The alarm fires (F). When a lack of emitted data points is detected, an internal reset period begins.

The following diagram shows a single internal reset period for metric stream A, from the times t5 to t15. At time t16, metric stream A is no longer evaluated.

Diagram depicting a single internal reset period.

The following diagram shows two internal reset periods for metric stream A, from the times t3 to t5, and from t6 to t16. A emits a data point at t6, starting another internal reset period. At time t17, metric stream A is no longer evaluated.

Diagram depicting two internal reset periods.
Threshold Alarm Example

A threshold alarm reports on metric streams that occur outside the threshold. When a previously problematic metric stream is absent, the alarm starts the internal reset period for the metric stream.

In this example, four metric streams are evaluated by a threshold alarm. The Console shows the initial Firing (1:30) and Ok (1:51) transition states. The internal reset period occurs while the alarm is in Firing state.

Example of a threshold alarm with four metric streams.

The internal reset period and other significant events in this example are described in the following table.

Time State Transition Events Notifications (see Message Types)
12:00 Ok Ok All emissions are within threshold. FIRING_TO_OK
1:30 Firing Firing Emission from resource1 exceeds threshold. OK_TO_FIRING
1:35 Firing -- No emission is detected for resource1. The alarm starts the internal reset period for resource1. --
1:38 Firing -- No emission is detected for resource2. The alarm starts the internal reset period for resource2. --
1:45 Firing -- The internal reset period ends for resource1, so the alarm no longer checks for emissions from resource1. However, the alarm is still Firing because resource2 is still in its own internal reset period. --
1:48 Ok Ok The internal reset period ends for resource2, so the alarm no longer checks for emissions from resource2. Emissions from the remaining resources (resource3 and resource4) are within threshold. RESET (sent after the three-minute slack period, at about 1:51)
Absence Alarm Example

An absence alarm reports on absent metric streams. When a metric stream is absent, the alarm starts the absence detection period for the metric stream (default of two hours, can be customized). After completion of the absence detection period, the alarm starts the internal reset period for the metric stream.

In this example, a metric stream is evaluated by an absence alarm that uses the default two-hour absence detection period and default three-minute slack period. The Console shows the initial Firing (2:00) and Ok (4:10) transition states. The internal reset period occurs while the alarm is in Firing state.

Example of an absence alarm with a single metric stream.

The internal reset period and other significant events in this example are described in the following table.

Time State Transition Events Notifications (see Message Types)
1:00 Ok -- Emissions are detected.
2:00 Firing Firing No emission is detected for resource-z. The alarm starts the absence detection period for resource-z. OK_TO_FIRING
4:00 Firing -- The absence detection period for resource-z ends. The alarm starts the internal reset period for resource-z. --
4:10 Ok Ok The internal reset period ends for resource-z, so the alarm no longer checks for emissions from resource-z. No metric streams are monitored by the alarm any more, so the alarm transitions to Ok state. RESET (sent after the three-minute slack period, at about 4:13)

Time Needed to Reflect Alarm Updates

Updates to alarms take up to five minutes to be reflected everywhere.

For example, if you update an alarm to split notifications, then it might take up to five minutes for metric stream status to be populated in the Console.

Searching for Alarms

Search for alarms using supported attributes.

For more information about Search, see Overview of Search. For attribute descriptions, see Alarm Reference.

Search-Supported Attributes for Alarms

  • id

  • displayName

  • compartmentId

  • metricCompartmentId

  • namespace

  • query

  • severity

  • destinations

  • suppression

  • isEnabled

  • lifecycleState

  • timeCreated

  • timeUpdated

  • tags

Message Types

The message type indicates the reason that the message was sent.

Note

The specified message type is sent at the indicated time plus the alarm's configured trigger delay, if any.

Repeat messages are also sent if configured in the alarm.

The following table lists the alarm state and transition for each message type.

Message type State Transition Comments
OK_TO_FIRING FIRING from OK to FIRING
FIRING_TO_OK OK from FIRING to OK
REPEAT FIRING -- This message type is sent when the alarm maintains the FIRING state, and the alarm is configured for repeat notifications.
RESET OK from FIRING to OK

Important: When a RESET status change occurs, look at the health of the resource.

This message type is sent when the alarm transitions to the OK state after one or more internal resets. An internal reset occurs when a metric stream that caused the alarm to transition to the FIRING state is continuously absent for the full internal reset period. A metric stream that's internally reset is no longer tracked by the alarm.

Possible causes for an absent metric stream: The resource that was emitting the metric might have been moved or terminated, or the metric might be emitted only on failure. For more information about the internal reset period, see About the Internal Reset Period.

Monitoring Concepts

The following concepts are essential to working with Monitoring.

aggregated data
The result of applying a statistic and interval to a selection of raw data points for a metric. For example, you can apply the statistic max and interval 1h (one hour) to the last 24 hours of raw data points for the metric CpuUtilization. Aggregated data is displayed in default metric charts in the Console. You can also build metric queries for specific sets of aggregated data. For instructions, see Viewing Default Metric Charts and Building Metric Queries.
alarm
The alarm query to evaluate and the notification destination to use when the alarm is in the firing state, along with other alarm properties.
To create an alarm, see Creating a Basic Alarm.
alarm query
The Monitoring Query Language (MQL) expression to evaluate for the alarm. An alarm query must specify a metric, statistic, interval, and a trigger rule (threshold or absence). The Alarms feature of the Monitoring service interprets results for each returned time series as a Boolean value, where zero represents false and a nonzero value represents true. A true value means that the trigger rule condition has been met.
To create a basic alarm query, see Creating a Basic Query to Generate an Alarm Metric Chart. To create an alarm, see Creating a Basic Alarm.
data point
A timestamp-value pair for the specified metric. Example: 2022-05-10T22:19:00Z, 10.4
A data point is either raw or aggregated. Raw data points are posted by the metric namespace to the Monitoring service using the PostMetricData operation. The frequency of the data points posted varies by metric namespace. For example, a custom namespace might send data points for a metric at a 20-second frequency.
Aggregated data points are the result of applying a statistic and interval to raw data points. The interval of the aggregated data points is specified in the SummarizeMetricsData request. For example, a request specifying the statistic sum and interval 1h (one hour) returns a sum value for each hour of available raw data points for the metric.
dimension
A qualifier provided in a metric definition. Example: Resource identifier (resourceId), provided in the definitions of oci_computeagent metrics. Use dimensions to filter or group metric data. Example dimension name-value pair for filtering by availability domain: availabilityDomain = "VeBZ:PHX-AD-1"
To select a dimension for a metric chart or query, see Selecting Dimensions to Filter Metrics and Selecting Dimensions for a Query.
To select an interval for an alarm, see Selecting the Interval for an Alarm Query.
frequency
The time period between each posted raw data point for a metric. (Raw data points are posted by the metric namespace to the Monitoring service.) While frequency varies by metric, default service metrics typically have a frequency of 60 seconds (one data point posted per minute). See also resolution.
interval
The time window used to convert the set of raw data points.
The timestamp of the aggregated data point corresponds to the end of the time window during which raw data points are assessed. For example, for a five-minute interval, the timestamp "2:05" corresponds to the five-minute time window from 2:00:n to 2:05:00.
This image shows how the timestamp of an aggregated data point corresponds to the interval.
The following example query (MQL expression) specifies a 5-minute interval. For valid interval options in MQL expressions, see Interval (Monitoring Query Language (MQL) Reference).
CpuUtilization[5m].max()
Note

Supported values for interval depend on the specified time range in the metric query (not applicable to alarm queries). More interval values are supported for smaller time ranges. For example, if you select one hour for the time range, then all interval values are supported. If you select 90 days for the time range, then only interval values between 1 hour and 1 day are supported.
To select an interval for a metric chart or query, see Changing the Interval for a Default Metric Chart and Selecting the Interval for a Query.
To select an interval for an alarm, see Selecting the Interval for an Alarm Query.
See also resolution.
message
The content that the Alarms feature of the Monitoring service publishes to topics in the alarm's configured notification destinations. A message is sent when the alarm transitions to another state, such as from OK to FIRING.
For more information about alarm messages, see Message Format and Examples.
metadata
A reference provided in a metric definition. Example: unit (bytes), provided in the definition of the oci_computeagent metric DiskBytesRead. Use metadata to determine additional information about a metric. For metric definitions, see Supported Services.
metric
A measurement related to health, capacity, or performance of a resource. Example: The oci_computeagent metric CpuUtilization, which measures usage of a compute instance. For metric definitions, see Supported Services.
Note

Metric resources don't have OCIDs .
metric definition
A set of references, qualifiers, and other information provided by a metric namespace for a metric. For example, the oci_computeagent metric DiskBytesRead is defined by dimensions (such as resource identifier) and metadata (specifying bytes for unit) as well as identification of its metric namespace (oci_computeagent). Each posted set of data points carries this information. Use the ListMetricData API operation to get metric definitions. For metric definitions, see Supported Services.
To select a metric name for a query, see Selecting the Metric Name for a Query.
To select a metric name for an alarm, see Creating a Basic Query to Generate an Alarm Metric Chart and Creating a Basic Alarm.
metric namespace
Indicator of the resource , service, or application that emits the metric. Provided in the metric definition. For example, the CpuUtilization metric definition emitted by the Oracle Cloud Agent software on compute instances  lists the metric namespace oci_computeagent as the source of the CpuUtilization metric. For metric definitions, see Supported Services.
To select a metric namespace for a metric chart or query, see Viewing Default Metric Charts for a Metric Namespace (Multiple Resources) and Selecting the Metric Namespace for a Query.
To select a metric namespace for an alarm, see Creating a Basic Query to Generate an Alarm Metric Chart and Creating a Basic Alarm.
metric stream
An individual set of aggregated data for a metric and zero or more dimension values.
In the Metric streams status page, each metric stream corresponds to a set of dimension key-value pairs.
In metric charts (in the Console), each metric stream is depicted as a line (unless you aggregate all metric streams).
The following image depicts metric streams in a chart. Each line in the chart corresponds to a metric stream.
This image depicts metric streams in a chart. Each line in the chart corresponds to a metric stream.
For example, consider a compartment containing three compute instances in the AD-1 availability domain (including two in the ipexample instance pool) and a fourth instance in the AD-2 availability domain. In this example, the CPU Utilization metric chart shows four lines (one per instance). When filtered by the AD-1 availability domain, the chart shows three lines. When further filtered by the ipexample instance pool, the chart shows two lines.
To select metric streams in a query, see Selecting Dimensions to Filter Metrics, Selecting Dimensions for a Query, and Selecting Dimensions for an Alarm Query.
To set up an alarm for notifications per metric stream, see Creating an Alarm That Splits Messages by Metric Stream and Scenario: Split Messages by Metric Stream.
notification destination
Details for sending messages when the alarm transitions to another state, such as from OK to FIRING. The details and setup might vary by destination service. Available destination services include Notifications and Streaming.
For the Notifications service, specify a topic. (If you're creating the topic for the alarm, also specify one or more subscription protocols (such as PagerDuty).
For the Streaming service, specify a stream.
For examples of alarm messages sent to topics and streams, see Example Alarm Messages.
To set up a notification destination in an alarm, see Defining Notifications for an Alarm.
Oracle Cloud Agent software
Software used by a compute instance to post raw data points to the Monitoring service. Automatically installed with the latest versions of supported images. See Enabling Monitoring for Compute Instances.
query
The Monitoring Query Language (MQL) expression and associated information (such as metric namespace) to evaluate for returning aggregated data. The query must specify a metric, statistic, and interval.
To create a metric query, see Creating a Query.
To create an alarm query, see Creating a Basic Query to Generate an Alarm Metric Chart.
resolution

The period between time windows, or the regularity at which time windows shift. For example, use a resolution of 1m to retrieve aggregations every minute.

Note

For metric queries, the interval  you select drives the default resolution  of the request, which determines the maximum time range of data returned.

For alarm queries, the specified interval  has no effect on the resolution  of the request. The only valid value of the resolution for an alarm query request is 1m. For more information about the resolution parameter as used in alarm queries, see Alarm.

As shown in the following illustration, resolution controls the start time of each aggregation window relative to the previous window while interval controls the length of the windows. Both requests apply the statistic max to the data within each five-minute window (from the interval), resulting in a single aggregated data point representing the highest CPUutilization counter for that window. Only the resolution value differs. This resolution changes the regularity at which the aggregation windows shift, or the start times of successive aggregation windows. Request A doesn't specify a resolution and thus uses the default value equal to the interval (5 minutes). This request's five-minute aggregation windows are thus taken from the sets of data points emitted from 0:n to 5:00, 5:n to 10:00, and so forth. Request B specifies a 1-minute resolution, so its five-minute aggregation windows are taken from the set of data points emitted every minute from 0:n to 5:00, 1:n to 6:00, and so forth.

This image shows how aggregation windows start according to the resolution.

To specify a nondefault resolution that differs from the interval, see Selecting a Nondefault Resolution for a Query and Creating an Alarm.

resource group
A custom string provided with a custom metric that can be used as a filter or to aggregate results. The resource group must exist in the definition of the posted metric. Only one resource group can be applied per metric.
To select a resource group in a query, see Selecting a Resource Group in a Query.
To select a resource group in an alarm query, see Selecting a Resource Group in an Alarm Query.
statistic
The aggregation function applied to the set of raw data points.
To select the statistic for a metric chart or query, see Changing the Statistic for a Default Metric Chart and Selecting the Statistic for a Query.
To select the statistic for an alarm query, see Selecting the Statistic for an Alarm Query.
suppression
A configuration to stop publishing messages during the specified time range. Useful for suspending alarm notifications during system maintenance.
To suppress alarms, see Suppressing a Single Alarm and Suppressing Multiple Alarms.
time range
The bounds (timestamps) of the metric data that you want. For example, the past hour.
To select the time range for a metric chart or query, see Changing the Time Range for Default Metric Charts, Changing the Time Range for a Custom Metric Chart, and Selecting a Nondefault Time Range for a Query.
trigger rule
The condition that must be met for the alarm to be in the firing state. A trigger rule can be based on a threshold or absence of a metric.
To set up a trigger rule in an alarm, see Adding Trigger Rules to an Alarm.

Availability

The Monitoring service is available in all Oracle Cloud Infrastructure commercial regions. See About Regions and Availability Domains for the list of available regions, along with associated locations, region identifiers, region keys, and availability domains.

Supported Services

The following services have resources or components that can emit metrics to Monitoring:

Resource Identifiers

Most types of Oracle Cloud Infrastructure resources have a unique, Oracle-assigned identifier called an Oracle Cloud ID (OCID). For information about the OCID format and other ways to identify your resources, see Resource Identifiers., see Resource Identifiers.

Note

Metric resources don't have OCIDs .

Ways to Access Monitoring

You can access Oracle Cloud Infrastructure (OCI) by using the Console (a browser-based interface), REST API, or OCI CLI. Instructions for using the Console, API, and CLI are included in topics throughout this documentation. For a list of available SDKs, see Software Development Kits and Command Line Interface.

Console: To access Monitoring using the Console, you must use a supported browser. To go to the Console sign-in page, open the navigation menu at the top of this page and select Infrastructure Console. You are prompted to enter your cloud tenant, your user name, and your password. Open the navigation menu  and select Observability & Management. Under Monitoring, select Service Metrics.

API: To access Monitoring through APIs, use Monitoring API for metrics and alarms and Notifications API for notifications (used with alarms).

CLI: See Command Line Reference for Monitoring and Command Line Reference for Notifications.

Authentication and Authorization

Each service in Oracle Cloud Infrastructure integrates with IAM for authentication and authorization, for all interfaces (the Console, SDK or CLI, and REST API).

An administrator in an organization needs to set up groups , compartments , and policies  that control which users can access which services, which resources, and the type of access. For example, the policies control who can create new users, create and manage the cloud network, create instances, create buckets, download objects, and so on. For more information, see Managing Identity Domains. For specific details about writing policies for each of the different services, see Policy Reference.

If you're a regular user (not an administrator) who needs to use the Oracle Cloud Infrastructure resources that the company owns, contact an administrator to set up a user ID for you. The administrator can confirm which compartment or compartments you can use.

For more information about user authorizations for monitoring, see IAM Policies.

Administrators: For common policies that give groups access to metrics, see Metric Access for Groups. For common alarm policies, see Alarm Access for Groups. To authorize resources, such as instances, to make API calls, add the resources to a dynamic group. Use the dynamic group's matching rules to add the resources, and then create a policy that allows that dynamic group access to metrics. See Metric Access for Resources.

Limits on Monitoring

See Monitoring Limits for a list of applicable limits and instructions for requesting a limit increase.

Other limits include the following.

Storage Limits

Item Time range stored
Metric definitions 90 days
Alarm history entries 90 days

Alarm Message Limits

The maximum number of messages per alarm evaluation depends on the alarm destination. Limits are associated with the Oracle Cloud Infrastructure service used for the destination.

Monitoring tracks 200,000 metric streams per alarm for qualifying events. For more information about alarm evaluations, see Alarm Evaluations on this page.

Alarm destination Delivery Maximum alarm messages per evaluation
topic (Notifications) At least once 60
stream (Streaming) At least once 100,000

For example, consider the following evaluations of an alarm that splits notifications among 200 metric streams, using a topic as its destination.

Alarm evaluation (time) Metric stream transition Generated messages Sent messages Dropped messages
00:01:00 110 metric streams transition from OK to FIRING. 110 60 50
00:02:00 90 metric streams transition from OK to FIRING. 90 60 30

When a topic or stream is overused, it can result in delayed alarm notifications. Overuse can occur when multiple resources are using that topic or stream.

Best Practices to Work Within Limits

When you expect a high volume of alarm notifications, follow these best practices to help prevent exceeding alarm message limits and associated delays.

  • Reserve a single topic or stream for use with a high-volume alarm. Don't use one topic or stream for multiple high-volume alarms.
  • If you expect more than 60 messages per minute, specify Streaming as the alarm destination.
  • Streams:
    • Create partitions based on expected load. See Limits on Streaming Resources.
    • If alarm messages exceed the stream space, then update the alarm to use a different stream that has more partitions. For example, if the original stream contains five partitions, create a stream with ten partitions and then update the alarm to use the new stream.
      Note

      To avoid missing messages, continue consuming the original stream until no more messages are received.
  • Increase limits for the tenancy:

Security

This topic describes security for Monitoring.

For information about how to secure Monitoring, including security information and recommendations, see Securing Monitoring.