[Yandex Cloud documentation](../../index.md) > [Monium](../index.md) > Concepts > Data retention period (TTL)

# Data retention period (TTL)

## Metrics retention period {#ttl-metrics}

# Deleting expired metrics (TTL)

In Monium.Metrics, there are two types of metrics:

* Custom metrics.
* System metrics automatically collected from all active Yandex Cloud resources.

Metrics for which no new values have been received for 30 days are considered expired and automatically deleted from Monium.Metrics. Automatic deletion of expired metrics is run once a day.

After you delete a resource, the collection of its metrics stops. The metrics data of deleted resources continues to be available for 30 days. After this period, metrics are automatically deleted.

Custom metrics (`service: custom`) delivered through the Unified Agent are not deleted. If they are no longer being collected, contact [support](https://center.yandex.cloud/support). Your storage quota will be increased or the retention period for such metrics will be reduced.

Some services have special conditions:

* For Yandex Managed Service for Prometheus®, there is a separate retention period [quota](../operations/prometheus/index.md#quotas-per-endpoint) for expired metrics.
* For Yandex Compute Cloud, expired metrics are stored for 7 days. For example, if your folder hosts a VM and you delete or stop it on `August 1, 2020`, its metrics will be available in Monium.Metrics until `August 8, 2020`.

To set a shorter retention period, contact [support](https://center.yandex.cloud/support).

## Log retention period {#ttl-logs}

# Log retention period (TTL)

The log retention period (TTL) in Monium is 31 days.

The retention period is calculated starting from the `time_unix_nano` event; after the `TTL` expires, the log lines are permanently deleted.