Quotas and limits

To ensure efficient operation, Cloud Monitoring imposes the following usage limits.

Custom metrics

Category	Maximum value
Custom metric descriptors per project¹	500
Labels per metric descriptor	10
String length for label key	100
String length for label value	1024
Time series included in a request²	200
Rate at which data can be written to a single time series³	one point each 10 seconds
Histogram buckets per custom distribution metric	200
External⁴ metric descriptors per project	10,000
Active time series from custom metrics per monitored resource⁵	200,000
Active time series from external metrics per monitored resource⁵	200,000

¹ This limit is imposed by Cloud Monitoring. Other services might impose lower maximum values.
² You can write only one data point for each time series in a request, so this limit also functions as the maximum number of points that can be written per request.
³ The Cloud Monitoring API requires that the end times of points written to a time series be at least 10 seconds apart. You can batch write points to a time series, provided that the data points are written in order.
⁴ External metrics are those written to external.googleapis.com. These metrics include those written by Prometheus, which is a monitoring tool often used with Kubernetes. See Using Prometheus for more information.
⁵ A time series is active if you have written data points to it within the previous 24 hours. For custom and external metrics, including Prometheus³ metrics, the limit applies to the total number of active time series across all custom metric types, or across all external metric types, for a single monitored resource. An exception is the global monitored resource, for which the limit applies to each metric type separately. This is a system-wide safety limit and isn't customizable.

Monitoring API quotas and limits

Category	Maximum value
Limits to API usage	See the Quotas dashboard. For an API, click All Quotas to see your quota.
Lifetime of API page tokens	24 hours

About Monitoring API quotas

The Monitoring API has quota limits for the rates of time-series ingestion requests and time-series queries. Ingestion requests are calls that write time-series data, and queries are calls that retrieve time-series data. There are also internal limits on other Monitoring API endpoints; these endpoints aren't intended to handle high rates of requests.

If you require higher Monitoring API quota limits, contact Google Cloud Support.

The other limits are fixed and as detailed on this page.

For more information, go to Working with quotas.

Data retention

Metric data points older than the retention period are deleted from time series.

Category	Value
Retention of data points from custom and external metric types^†	24 months
Retention of data points from process-health metric types^‡	24 hours
Retention of data points from all other metric types	6 weeks
Lifetime of API page tokens	24 hours

^† Metric data is stored for 6 weeks at its original sampling frequency, then it is down-sampled to 10-minute intervals for extended storage.
^‡ Process-health metrics are the agent.googleapis.com/agent/processes metrics that do not include count_by_state or fork_count in the metric-type string. The count_by_state and fork_count metrics are retained for 6 weeks.

Resource groups

Category	Value
Number of resource groups per Workspace	500
Maximum number of groups included in an email report¹	10

¹ When you configure Cloud Monitoring email reports, you can request information on utilization of your resource groups. Due to a limitation in the email reporter, the generated reports include information for only 10 groups.

Workspace limits

A Workspace can contain up to 100 Google Cloud projects. See Using Workspaces for more information.

Limits for alerting and uptime checks

Category	Value
Uptime checks per Workspace	100^*
Alerting policies per Workspace	500
Conditions per alerting policy	6
Notification channels per alerting policy	16
Notification channels per Workspace	4000
Simultaneously open incidents per alerting policy	5000
Maximum duration for a metric-absence condition	1 day
Maximum duration for a metric-threshold condition	23 hours 30 minutes

^*This limit applies to the number of uptime-check configurations. Each uptime-check configuration includes the time interval between testing the status of the specified resource. See Managing uptime checks for more information.

Limits for charting

Category	Value
Dashboards per Workspace	1000
Charts on a dashboard	25
Lines on a chart	300

Service-level objectives

Category	Value
Number of SLOs per service	500