Add percentage based retention by ldufr · Pull Request #18080 · prometheus/prometheus

ldufr · 2026-02-13T10:39:47Z

Initially proposed in #10287 and implemented #12278, I wanted to help bring this PR to an end.

The command line --storage.tsdb.retention.percentage wasn't added, because --storage.tsdb.retention.time and --storage.tsdb.retention.size are marked as deprecated. Instead, it's only possible to specify the value with the config file.

Which issue(s) does the PR fix:

Fixes #10287

Does this PR introduce a user-facing change?

[FEATURE] Add `storage.tsdb.retention.percentage` configuration and command line option to configure the maximum percent of disk usable for TSDB storage.

roidelapluie · 2026-02-13T11:52:48Z

I am fine with NOT adding the flag.

bboreham · 2026-02-16T21:35:43Z

To clarify, you wish to take over this work because messages on #12278 indicated that the last person didn't have bandwidth to do it?

If so, please post a message on that PR so other people can see.

ldufr · 2026-02-17T07:33:45Z

Sounds good, I had talked with @krajorama about it, but will add the message to the PR.

krajorama

Minor comments.

krajorama

We're getting there, a few small comments.
The one thing I realized was missing is the test coverage, ideally we'd have some test for behavior in BeyondSizeRetention in db.go , but that needs some kind of dependency injection of faking the FsSize call.

krajorama

LGTM, found one real issue with AI, plz fix and then we can merge.

roidelapluie · 2026-02-20T10:28:32Z

I believe it would be better to have a single lock in func (db *DB) getRetentionSettings() (int64, uint) {

I also do not see changes in ApplyConfig to change the variable on config reload.

Signed-off-by: Jérôme LOYET <822436+fatpat@users.noreply.github.com> Signed-off-by: Laurent Dufresne <laurent.dufresne@grafana.com>

…ding Signed-off-by: Laurent Dufresne <laurent.dufresne@grafana.com>

Signed-off-by: Laurent Dufresne <laurent.dufresne@grafana.com>

roidelapluie · 2026-02-24T14:50:43Z

Thanks!

##### [\`v3.11.0\`](https://github.com/prometheus/prometheus/releases/tag/v3.11.0) - \[CHANGE] Hetzner SD: The `__meta_hetzner_datacenter` label is deprecated for the role `robot` but kept for backward compatibility, use the `__meta_hetzner_robot_datacenter` label instead. For the role `hcloud`, the label is deprecated and will stop working after the 1 July 2026. [#17850](prometheus/prometheus#17850) - \[CHANGE] Hetzner SD: The `__meta_hetzner_hcloud_datacenter_location` and `__meta_hetzner_hcloud_datacenter_location_network_zone` labels are deprecated, use the `__meta_hetzner_hcloud_location` and `__meta_hetzner_hcloud_location_network_zone` labels instead. [#17850](prometheus/prometheus#17850) - \[CHANGE] Promtool: Redirect debug output to stderr to avoid interfering with stdout-based tool output. [#18346](prometheus/prometheus#18346) - \[FEATURE] AWS SD: Add Elasticache Role. [#18099](prometheus/prometheus#18099) - \[FEATURE] AWS SD: Add RDS Role. [#18206](prometheus/prometheus#18206) - \[FEATURE] Azure SD: Add support for Azure Workload Identity authentication method. [#17207](prometheus/prometheus#17207) - \[FEATURE] Discovery: Introduce `prometheus_sd_last_update_timestamp_seconds` metric to track the last time a service discovery update was sent to consumers. [#18194](prometheus/prometheus#18194) - \[FEATURE] Kubernetes SD: Add support for node role selectors for pod roles. [#18006](prometheus/prometheus#18006) - \[FEATURE] Kubernetes SD: Introduce pod-based labels for deployment, cronjob, and job controller names: `__meta_kubernetes_pod_deployment_name`, `__meta_kubernetes_pod_cronjob_name` and `__meta_kubernetes_pod_job_name`, respectively. [#17774](prometheus/prometheus#17774) - \[FEATURE] PromQL: Add `</` and `>/` operators for trimming observations from native histograms. [#17904](prometheus/prometheus#17904) - \[FEATURE] PromQL: Add experimental `histogram_quantiles` variadic function for computing multiple quantiles at once. [#17285](prometheus/prometheus#17285) - \[FEATURE] TSDB: Add `storage.tsdb.retention.percentage` configuration to configure the maximum percent of disk usable for TSDB storage. [#18080](prometheus/prometheus#18080) - \[FEATURE] TSDB: Add an experimental `fast-startup` feature flag that writes a `series_state.json` file to the WAL directory to track active series state across restarts. [#18303](prometheus/prometheus#18303) - \[FEATURE] TSDB: Add an experimental `st-storage` feature flag. When enabled, Prometheus stores ingested start timestamps (ST, previously called Created Timestamp) from scrape or OTLP in the TSDB and Agent WAL, and exposes them via Remote Write 2. [#18062](prometheus/prometheus#18062) - \[FEATURE] TSDB: Add an experimental `xor2-encoding` feature flag for the new TSDB block float sample chunk encoding that is optimized for scraped data and allows encoding start timestamps. [#18062](prometheus/prometheus#18062) - \[ENHANCEMENT] HTTP client: Add AWS `external_id` support for sigv4. [#17916](prometheus/prometheus#17916) - \[ENHANCEMENT] Kubernetes SD: Deduplicate deprecation warning logs from the Kubernetes API to reduce noise. [#17829](prometheus/prometheus#17829) - \[ENHANCEMENT] TSDB: Remove old temporary checkpoints when creating a Checkpoint. [#17598](prometheus/prometheus#17598) - \[ENHANCEMENT] UI: Add autocomplete support for experimental `first_over_time` and `ts_of_first_over_time` PromQL functions. [#18318](prometheus/prometheus#18318) - \[ENHANCEMENT] Vultr SD: Upgrade govultr library from v2 to v3 for continued security patches and maintenance. [#18347](prometheus/prometheus#18347) - \[PERF] PromQL: Improve performance and reduce heap allocations in joins (VectorBinop)/And/Or/Unless. [#17159](prometheus/prometheus#17159) - \[PERF] PromQL: Partially address performance regression in native histogram aggregations due to using `KahanAdd`. [#18252](prometheus/prometheus#18252) - \[PERF] Remote write: Optimize WAL watching used for RW sending to reuse internal buffers. [#18250](prometheus/prometheus#18250) - \[PERF] TSDB: Optimize LabelValues intersection performance for matchers. [#18069](prometheus/prometheus#18069) - \[PERF] UI: Skip restacking on hover in stacked series charts. [#18230](prometheus/prometheus#18230) - \[BUGFIX] AWS SD: Fix EC2 SD ignoring the configured `endpoint` option, a regression from the AWS SDK v2 migration. [#18133](prometheus/prometheus#18133) - \[BUGFIX] AWS SD: Fix panic in EC2 SD when DescribeAvailabilityZones returns nil ZoneName or ZoneId. [#18133](prometheus/prometheus#18133) - \[BUGFIX] Agent: Fix memory leak caused by duplicate SeriesRefs being loaded as active series. [#17538](prometheus/prometheus#17538) - \[BUGFIX] Alerting: Fix alert state incorrectly resetting to pending when the FOR period is increased in the config file. [#18244](prometheus/prometheus#18244) - \[BUGFIX] Azure SD: Fix system-assigned managed identity not working when `client_id` is empty. [#18323](prometheus/prometheus#18323) - \[BUGFIX] Consul SD: Fix filter parameter not being applied to health service endpoint, causing Node and Node.Meta filters to be ignored. [#17349](prometheus/prometheus#17349) - \[BUGFIX] Kubernetes SD: Fix duplicate targets generated by `*DualStack` EndpointSlices policies. [#18192](prometheus/prometheus#18192) - \[BUGFIX] OTLP: Fix ErrTooOldSample being returned as HTTP 500 instead of 400 in PRW v2 histogram write paths, preventing infinite client retry loops. [#18084](prometheus/prometheus#18084) - \[BUGFIX] OTLP: Fix exemplars getting mixed between incorrect parts of a histogram. [#18056](prometheus/prometheus#18056) - \[BUGFIX] PromQL: Do not skip histogram buckets in queries where histogram trimming is used. [#18263](prometheus/prometheus#18263) - \[BUGFIX] Remote write: Fix `prometheus_remote_storage_sent_batch_duration_seconds` measuring before the request was sent. [#18214](prometheus/prometheus#18214) - \[BUGFIX] Rules: Fix alert state restoration when rule labels contain Go template expressions. [#18375](prometheus/prometheus#18375) - \[BUGFIX] Scrape: Fix panic when parsing bare label names without an equal sign in brace-only metric notation. [#18229](prometheus/prometheus#18229) - \[BUGFIX] TSDB: Fail early when `use-uncached-io` feature flag is set on unsupported environments. [#18219](prometheus/prometheus#18219) - \[BUGFIX] TSDB: Fall back to CLI flag values when retention is removed from config file. [#18200](prometheus/prometheus#18200) - \[BUGFIX] TSDB: Fix memory leaks in buffer pools by clearing reference fields before returning buffers to pools. [#17895](prometheus/prometheus#17895) - \[BUGFIX] TSDB: Fix missing mmap of histogram chunks during WAL replay. [#18306](prometheus/prometheus#18306) - \[BUGFIX] TSDB: Fix storage.tsdb.retention.time unit mismatch in file causing retention to be 1e6 times longer than configured. [#18200](prometheus/prometheus#18200) - \[BUGFIX] Tracing: Fix missing traceID in query log when tracing is enabled, previously only spanID was emitted. [#18189](prometheus/prometheus#18189) - \[BUGFIX] UI: Fix tooltip Y-offset drift when using multiple graph panels. [#18228](prometheus/prometheus#18228) - \[BUGFIX] UI: Update retention display in runtime info when config is reloaded. [#18200](prometheus/prometheus#18200)

ldufr requested review from a team, bwplotka, codesome, jesusvazquez and krajorama as code owners February 13, 2026 10:39

ldufr force-pushed the ldufresne/retention-size-percentage branch 3 times, most recently from be931a9 to e8ee5e1 Compare February 13, 2026 11:47

ldufr force-pushed the ldufresne/retention-size-percentage branch from e8ee5e1 to 50aa49b Compare February 13, 2026 11:53

ldufr mentioned this pull request Feb 17, 2026

Add --storage.tsdb.retention.percentage (#10287) #12278

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krajorama self-assigned this Feb 17, 2026

krajorama reviewed Feb 17, 2026

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ldufr force-pushed the ldufresne/retention-size-percentage branch from 50aa49b to 46cb1a5 Compare February 18, 2026 09:17

ldufr requested a review from krajorama February 18, 2026 13:21

krajorama reviewed Feb 19, 2026

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Comment thread docs/configuration/configuration.md

Comment thread util/runtime/statfs_unix_test.go Outdated

Comment thread util/runtime/statfs_windows.go Outdated

Comment thread util/runtime/statfs_windows_test.go Outdated

ldufr force-pushed the ldufresne/retention-size-percentage branch from 46cb1a5 to 91860b4 Compare February 19, 2026 13:07

ldufr requested a review from krajorama February 19, 2026 17:54

krajorama reviewed Feb 20, 2026

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Comment thread tsdb/db.go Outdated

ldufr force-pushed the ldufresne/retention-size-percentage branch from 91860b4 to fd15f3e Compare February 20, 2026 10:09