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JMX

Learn how the JMX integration connects with Netdata and how to configure it.

Guides

Cassandra Operations Guides 1 page

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Cassandra monitoring checklist: the signals every production cluster needs

A tiered checklist of Cassandra monitoring signals, from survival-level liveness checks to expert-level composite alerting patterns.

Kafka Operations Guides 16 pages

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Kafka __consumer_offsets growing huge: compaction failure on the offsets topic

Diagnose and fix unbounded growth of Kafka's __consumer_offsets topic caused by a stalled or crashed log cleaner thread.

Kafka Broker Out Of Disk: How To Fix It

Diagnose and recover when a Kafka broker exhausts disk space on its log directories, including the cliff-edge shutdown behavior, uneven directory fill, and silent compaction failures.

Kafka consumer group lag growing: detection, lag-as-time, and root causes

Diagnose growing Kafka consumer group lag, convert offsets to time, and identify root causes from slow consumers to broker-side page cache and disk bottlenecks.

Kafka disk I/O latency high: await, LocalTimeMs, and the slow-disk broker

Diagnose elevated disk I/O latency on Kafka brokers using iostat await and LocalTimeMs. Distinguish disk degradation from page cache misses and transient load.

Kafka FailedProduceRequestsPerSec rising: the single best 'producers are hurting' signal

Diagnose rising Kafka FailedProduceRequestsPerSec, correlate with ISR and replication health, and stop producer-visible failures before they cascade.

Kafka fetch request latency high: FetchConsumer vs FetchFollower and page cache misses

Diagnose elevated Kafka fetch request latency by distinguishing consumer fetches from replica fetches and identifying page cache misses as the root cause.

Kafka ISR shrinking: IsrShrinksPerSec, flapping, and the cascade to offline

Diagnose ISR shrink storms, flapping replicas, and the cascade to offline partitions in Kafka production clusters.

Kafka JVM heap and Full GC pauses: ISR drops, session timeouts, and right-sizing the heap

Diagnose and fix Kafka broker JVM heap pressure and Full GC pauses that trigger ISR shrinks, ZooKeeper session timeouts, and request latency spikes.

Kafka log compaction falling behind: the dead cleaner thread and unbounded disk growth

Diagnose and fix silent Kafka log cleaner thread crashes that cause compacted topics like __consumer_offsets to grow without bound.

Kafka NetworkProcessorAvgIdlePercent low: network thread saturation and TLS overhead

Diagnose and fix low NetworkProcessorAvgIdlePercent in Kafka, including network thread saturation from TLS handshakes, connection storms, and large fetch responses.

Kafka replica MaxLag growing: slow followers and replica fetcher health

Diagnose and fix growing Kafka replica fetcher lag before it triggers ISR shrinks and write rejections.

Kafka REQUEST_TIMED_OUT: produce requests that expire before replication completes

Diagnose and fix Kafka REQUEST_TIMED_OUT errors when acks=all produce requests expire waiting for replication, request queue backup, or slow disk.

Kafka Too many open files: file descriptor exhaustion from segments and connections

Diagnose and fix Kafka broker file descriptor exhaustion caused by log segments and network connections, including quick checks, fixes, and prevention.

Kafka UncleanLeaderElectionsPerSec > 0: confirmed silent data loss

What to do when Kafka's UncleanLeaderElectionsPerSec metric rises above zero, confirming silent data loss, and how to recover without deepening the damage.

Kafka UnderMinIsrPartitionCount: confirming the write path is blocked

How to read Kafka's UnderMinIsrPartitionCount metric, distinguish it from under-replication, and confirm producers are actively blocked.

Kafka UnderReplicatedPartitions > 0: the most important metric and how to clear it

Troubleshoot and clear Kafka under-replicated partitions by identifying lagging followers, correlating disk, network, and GC signals, and applying the right fix without causing further ISR shrink.

Academy

JMX Monitoring

Learn everything about monitoring & troubleshooting JMX, what metrics are important to monitor and why, and how to monitor JMX with Netdata.

Resources

10 Best Apache Tomcat Monitoring Tools in 2026

We ranked the 10 best Apache Tomcat monitoring tools on JVM and JMX metric depth, setup time, data resolution, alerting, and total cost. See our picks.

Blog

Cassandra Monitoring: Key Metrics & Best Practices

Strategies For Ensuring Peak Performance & Stability