MongoDB only stays running for a few days. Why? Main process exited, code=dumped, status=6/ABRT

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Summary

MongoDB v8.0.17 on Ubuntu 24.04 crashes after a few days with core dump (signal=ABRT). The issue is caused by memory corruption leading to a segmentation fault, triggered by intensive write operations or large dataset handling.

Root Cause

  • Memory corruption in the MongoDB process, resulting in a segmentation fault.
  • Triggered by high write throughput or large dataset manipulations.
  • ABRT (signal 6) indicates an abnormal termination due to unhandled exceptions or memory errors.

Why This Happens in Real Systems

  • Long-running processes accumulate memory fragmentation or leaks.
  • Intensive write operations stress memory allocation/deallocation.
  • Ubuntu 24.04 kernel/glibc optimizations may expose latent bugs in MongoDB v8.0.17.

Real-World Impact

  • Downtime: Database unavailability after crashes.
  • Data Integrity Risk: Potential for incomplete writes or corruption.
  • Resource Waste: Frequent restarts consume CPU/memory inefficiently.

Example or Code (if necessary and relevant)

# Check for core dumps
ls -l /var/lib/mongodb/core.*

# Analyze core dump (example using gdb)
gdb /usr/bin/mongod /var/lib/mongodb/core.652376
(gdb) bt

How Senior Engineers Fix It

  • Upgrade MongoDB: Move to a newer version with memory management fixes.
  • Enable AddressSanitizer: Compile MongoDB with -fsanitize=address to detect memory errors.
  • Tuning: Reduce wiredTigerCacheSizeGB or increase journalCommitIntervalMs.
  • Kernel Updates: Ensure Ubuntu 24.04 has the latest kernel patches.

Why Juniors Miss It

  • Overlook core dumps: Failing to analyze /var/lib/mongodb/core.* files.
  • Blame OS/hardware: Assume it’s a system issue without investigating MongoDB-specific memory patterns.
  • Ignore logs: Miss critical clues like segmentation fault or memory allocation failed.

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