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Database Monitoring Software Without Query Languages

Database monitoring for MySQL, PostgreSQL, SQL Server, Oracle & MongoDB with per-second query insights, deadlock detection & AI root cause. Try free today!

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Monitor every database in real time with per-second precision, AI root-cause detection, and 60-second deployment for full visibility. Book a demo now!

Integrations

MongoDB (Exporter)

Learn how the MongoDB (Exporter) integration connects with Netdata and how to configure it.

MongoDB (go.d.plugin mongodb)

Monitor MongoDB operations, transactions, clients, replication, sharding, storage, and resource usage.

Guides

Guides overview 1 page

MongoDB Operations Guides

Practical guides for running, troubleshooting, and monitoring MongoDB in production.

MongoDB Operations Guides 32 pages

Open the MongoDB Operations Guides hub

MongoDB Application Thread Evictions: How To Fix

Diagnose and fix WiredTiger cache eviction stalls when MongoDB application threads start evicting pages, causing sudden latency spikes.

MongoDB Balancer Stuck On Jumbo Chunks: Fix It

Diagnose and fix permanent shard imbalance in MongoDB caused by a stuck balancer or jumbo chunks that cannot migrate.

MongoDB cache too small: sizing the WiredTiger cache for your working set

Size the WiredTiger cache to fit your working set. Covers default calculations, explicit overrides, container limits, and the signals that warn you before eviction stalls.

MongoDB checkpoint duration climbing: diagnosing slow WiredTiger checkpoints

Diagnose and fix climbing WiredTiger checkpoint duration before it exceeds the 60-second interval and freezes writes.

MongoDB checkpoint stall write freeze: when all writes stop with no error

Troubleshoot the WiredTiger checkpoint stall that silently blocks all MongoDB writes with no errors, leaving reads partially functional.

MongoDB connection churn: high totalCreated rate and thread creation overhead

Diagnose and fix MongoDB connection churn where a climbing totalCreated delta with stable current connections drives thread creation overhead and latency.

MongoDB connection refused at maxIncomingConnections: hitting the connection ceiling

Diagnose and resolve MongoDB connection refusals when inbound connections hit the maxIncomingConnections ceiling or OS file descriptor limits.

MongoDB connection storm spiral: reconnection floods after an election or deploy

Diagnose and break MongoDB connection storm spirals caused by elections, deploys, or network blips. Recognize RSS spikes, ticket contention, and totalCreated churn before they crash the node.

MongoDB disk full: emergency recovery when mongod can't write the journal

Emergency triage and recovery steps when MongoDB exhausts disk space and the journal cannot write, including WiredTiger space reclamation and recovery procedures.

MongoDB disk I/O saturation: correlating iostat with WiredTiger signals

Diagnose MongoDB storage bottlenecks by correlating OS disk saturation signals with WiredTiger checkpoint, journal, and cache metrics.

MongoDB exceeded memory limit for $group — aggregation spills and allowDiskUse

Fix MongoDB aggregation pipeline errors when $group or $sort hit the 100MB memory limit, diagnose disk spills, and restructure pipelines for production stability.

MongoDB exposed to the internet without authentication: bindIp and the breach scenario

Detect and remediate MongoDB instances bound to public interfaces with authentication disabled, closing the attack surface created by net.bindIp misconfiguration.

MongoDB journal sync latency high: the storage signal that warns 60 seconds early

Detect, diagnose, and fix high WiredTiger journal sync latency in MongoDB before it stalls j:true and w:majority writes.

MongoDB lock wait times: collection and metadata lock contention during DDL

Diagnose and fix high MongoDB collection and metadata lock wait times caused by DDL operations such as createIndex, dropIndex, and collMod.

MongoDB long-running operations: finding and killing the query holding a ticket

Find and terminate long-running MongoDB operations that are blocking others by holding WiredTiger tickets, using currentOp, killOp, and related diagnostic signals.

MongoDB monitoring checklist: the signals every production cluster needs

A leveled checklist of production MongoDB monitoring signals covering liveness, replication, WiredTiger cache, tickets, connections, and disk saturation.

MongoDB no primary / election storm: repeated elections and write outages

Diagnose and stop MongoDB replica set election storms where primaries repeatedly step down, causing rolling 2-12 second write outages.

MongoDB not master error: writes hitting a non-primary node after failover

Troubleshoot and fix MongoDB NotWritablePrimary errors that occur when applications write to a non-primary node after failover or election.

MongoDB not primary and secondaryOk=false: reading from a secondary and how to fix it

Fix MongoDB NotPrimaryNoSecondaryOk errors when clients route reads to secondaries without the correct read preference, and prevent stale topology failures after failover.

MongoDB OOM-killed by the kernel: RSS, cache sizing, and oom_score_adj

Diagnose and prevent Linux OOM kills targeting mongod by understanding RSS composition, WiredTiger cache sizing, and oom_score_adj protection.

MongoDB operation exceeded time limit (MaxTimeMSExpired): maxTimeMS and killed operations

Diagnose MongoDB MaxTimeMSExpired errors. Understand why maxTimeMS kills operations, how to distinguish server-side timeouts from client socket timeouts, and how to find root causes with currentOp and the slow query log.

MongoDB oplog window collapse: secondaries falling off and forced full resync

Diagnose and fix MongoDB oplog window collapse when write surges shrink the replication window and force secondaries into RECOVERING state.

MongoDB oplog window too small: sizing the oplog for your write volume

Size and monitor the MongoDB oplog window to prevent secondaries from falling off and forcing full resyncs. Production rules, resize commands, and thresholds.

MongoDB page faults high: working set exceeding memory after warmup

Diagnose and fix sustained high page fault rates in MongoDB when the working set exceeds both WiredTiger cache and OS page cache after warmup.

MongoDB rollback after failover: silent data loss and the rollback directory

Understand MongoDB rollback after failover, recover data from the rollback directory, and prevent silent data loss with majority write concern.

MongoDB RSS growing without cache growth: leaks, threads, and tcmalloc fragmentation

Diagnose why MongoDB resident memory grows while WiredTiger cache stays flat. Covers tcmalloc fragmentation, connection thread stacks, cursor leaks, and version-specific allocator changes.

MongoDB silent index regression: when a dropped index quietly becomes a collection scan

Diagnose and fix the failure mode where MongoDB queries silently switch to collection scans after an index drop or planner regression, causing read latency to grow with collection size.

MongoDB slow query COLLSCAN: collection scans and the missing index

Diagnose and fix MongoDB collection scans (COLLSCAN) that cause slow queries by identifying missing indexes, query plan regressions, and inefficient predicates.

MongoDB ticket exhaustion: WiredTiger read/write tickets and queued operations

Diagnose and fix MongoDB WiredTiger ticket exhaustion when read or write tickets approach zero and operations queue.

MongoDB too stale to catch up: secondary stuck in RECOVERING and how to resync

Diagnose and recover a MongoDB secondary that has fallen past the primary's oplog window, is stuck in RECOVERING, and requires a full initial sync.

MongoDB WiredTiger cache dirty ratio high: the leading indicator nobody watches

Learn why WiredTiger dirty ratio is a stronger leading indicator than cache fill, how to diagnose it before latency spikes, and what to fix.

MongoDB WiredTiger cache pressure cascade: eviction stalls and latency spikes

Diagnose and break the MongoDB WiredTiger cache pressure cascade before eviction stalls and latency spikes bring down your replica set.

Academy

How to Troubleshoot Slow Queries in MongoDB

A Beginner’s Guide to Optimizing MongoDB Performance

MongoDB Monitoring

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

Resources

Best MongoDB Monitoring Tools (10 Ranked for 2026)

We ranked 10 best MongoDB monitoring tools on metric depth, collection granularity, query-level insight and cost of ownership. See which fits your stack.

Webinar: Live Database & Network Diagnostics

See how Netdata's new Live Functions let you analyze slow queries, detect deadlocks, and monitor SNMP network interfaces directly from the Netdata dashboard, with a live demo.

Blog

Database Performance Monitoring: 14+ DBs Supported

Slow queries, running operations, deadlocks, and errors for PostgreSQL, MySQL, MongoDB, SQL Server, Oracle, and more.

Release 1.21: New Collectors & Faster Exporters

Upgrading Monitoring Performance and Flexibility

Release 1.17: Collection frequency gets flexible

Continuing to Enhance Monitoring with Latest Updates