Summary

This incident highlights a critical misunderstanding about Rclone behavior during file synchronization.

Root Cause

• Misinterpretation of Rclone sync properties
• Incorrect configuration of data exclusion rules
• Lack of clear documentation on what sync actually does

Why This Happens in Real Systems

• Rclone sync is designed to keep the destination in sync with the source
• It copies only changed or added files, not deleted ones from backblaze
• The management of data sources and sinks can lead to unexpected redirects

Real-World Impact

• Unintended duplication of files
• Wasted storage resources
• Potential security risks if sensitive data is exposed

Example or Code (if necessary and relevant)

rclone sync /mnt/backup/storage crypt-storage: --max-age 24h --no-traverse --exclude '/rdiff-backup-data/**'

Avoid using –exclude unless you want to filter out checkpoints or intermediate structures.

How Senior Engineers Fix It

• Review the Rclone documentation thoroughly
• Use proper sync options to reflect actual data movement
• Implement logging and monitoring for sync status

Why Juniors Miss It

• Overlooking key flags and their effects
• Assuming default behavior without testing
• Lack of understanding of remote sync architectures

CRITICAL RULES (MANDATORY)

• Use bold for key takeaways and concepts
• Use bullet lists to explain causes and impacts