Data retention

By default, Pyroscope stores data indefinitely without any downsampling, which can create storage concerns. Pyroscope offers two complementary approaches to manage data retention.

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Pyroscope server does not delete data from the disk immediately to avoid excessive disk IO, therefore you may observe that the disk usage continues growing even when a retention policy is enforced. Typically, the lag does not exceed 1-3 GB.

Time-based retention policy

You can configure a specific period of time for which data will be stored in the Pyroscope configuration file. For example:

retention: 720h # 30 days

Note that Pyroscope uses a separate storage for exemplars created using tracing integration, and allows configuring the retention period for them separately:

exemplars-retention: 72h # 3 days

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The standard Go time duration format is used.

See the server configuration page for more details on the Pyroscope configuration file.

Pyroscope periodically deletes data that has passed the threshold: the process can take some time and cause an increase in memory and CPU consumption, especially if the retention policy has been enabled for the first time.

Level-based retention policy

Pyroscope stores profiling data in a specific structure called segment tree. This tree can be described as a multi-level structure where every level is an aggregation of the lower levels. Thus, at level 0 each element represents 10s time range, 100s at level 1, 1000s at level 2, and so forth.

Segment nodes at levels 0 and 1 account for up to 90% of the disk space used, meanwhile those are accessed rarely, only when a narrow time range is queried. A natural solution is to keep the high precision raw data for only a limited time, and store the lower precision, summarized data longer.

Level-based retention policy enables you to significantly reduce disk space requirements by downsampling. A retention period can be configured for every of the 3 lowest segment tree levels:

retention-levels: 0: 720h  # 30 days 1: 2160h # 90 days 2: 8760h # 365 days

Time-based and level-based retention policies can be used in-conjunction:

retention: 8760h # 365 daysretention-levels: 0: 720h  # 30 days 1: 2160h # 90 days

When a query targets deleted data from these levels, Pyroscope fetches downsampled data from the higher level of the affected segment tree node. Note that the data returned will be slightly less precise – although in practice the difference is insignificant, this fact should be taken into account.

Visit demo.pyroscope.io to see level-based retention policy in action.