---
title: "The value of soak testing | Grafana Labs"
description: "Learn why soak tests find failures that short average-load runs miss by targeting time-dependent degradation."
---

> For a curated documentation index, see [llms.txt](/llms.txt). For the complete documentation index, see [llms-full.txt](/llms-full.txt).

# The value of soak testing

Average-load and baseline tests show how the system behaves under expected traffic for a short window. [Soak testing](/docs/k6/latest/testing-guides/test-types/soak-testing/) reuses that load level and holds the plateau longer so degradation that needs time to accumulate becomes visible.

Stress and spike tests answer overload and burst questions. Soak testing answers a duration question: does performance or stability drift when load stays near average levels for hours?

## Problems short runs miss

A five-minute stress run cannot expose a leak that adds 50 MB per hour. A ten-minute breakpoint ramp may not reveal a connection pool that loses handles only under sustained traffic. Those defects need a longer plateau at moderate load.

Common patterns soak tests target:

- **Memory leaks**: Allocations that are never freed. Server memory climbs; `http_req_duration` in k6 may rise if garbage-collection pauses or queueing increase. Confirm with application memory metrics on the system under test.
- **Connection pool limits**: Connections acquired but not returned under certain errors. Short tests look healthy; after hours, new requests block and latency or errors increase.
- **Log and disk fill**: Verbose logging or temp files that grow without rotation. Performance can change suddenly when disk space runs out.
- **Gradual latency creep**: Fragmented indexes, full caches, or backlog growth. p95 drifts upward slowly enough that point-in-time alerts never fire.

## How soak differs from other test types

In k6 docs, soak is a variation of **average-load** testing: same ramp-up and ramp-down pattern, longer plateau. Load stays near the average level you measured in baseline work, not at stress-test peaks.

In the next milestone, you design a soak profile with that longer plateau.