> ## Documentation Index
> Fetch the complete documentation index at: https://docs.vortexiq.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# JVM Heap Used %, Apache Cassandra KPI card, Vortex IQ Nerve Centre

> Cassandra runs on the JVM - heap >75% drives GC pauses; sustained high heap precedes node instability.

**[Nerve Centre KPIs](/nerve-centre/kpi-cards/cassandra) · [Audit Profile](/nerve-centre/kpi-cards/cassandra/audit) · [Sentiment Settings](/nerve-centre/kpi-cards/cassandra/sentiment)**

## At a glance

* **Category:** Capacity
* **Type:** Key Metrics
* **Chart:** gauge
* **Format:** percent
* **Time window:** RT/1m
* **Alert trigger:** >75%

## Calculation

Cassandra runs on the JVM - heap >75% drives GC pauses; sustained high heap precedes node instability.

## Known limitations

*Known limitations, FAQs, or reconciliation notes specific to this card. Replace this block when authored.*