Ubuntu 14.04 LTS – rsyslog causes excessive disk I/O and latency – Fix & Prevention

📖 ~1 min read

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

Intense logging drives disk wait times and slows application responses.

Environment & Reproduction

Appears during bursty events with synchronous disk writes.

Root Cause Analysis

Inefficient rsyslog rules and flush behavior amplify I/O pressure.

Quick Triage

Confirm rsyslog process contribution to disk wait and queue size.

Step-by-Step Diagnosis

Inspect rsyslog config, action queues, and destination write patterns.

Solution – Primary Fix

Enable buffered async writes and reduce noisy log categories.

Solution – Alternative Approaches

Forward high-volume streams to remote collector to offload disk.

Verification & Acceptance Criteria

Disk wait declines and service latency returns to baseline.

Rollback Plan

Revert rsyslog tuning if required logs are unexpectedly dropped.

Prevention & Hardening

Define log budgets and backpressure-safe log routing strategy.

Related Errors & Cross-Refs

Common with /var capacity exhaustion and noisy debug logging.

Related tutorial: View the step-by-step tutorial for Ubuntu 14.04 LTS.

View all Ubuntu 14.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

rsyslog performance tuning and Linux I/O analysis docs.