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Case Study #182 — 300 Software Failure Case Studies

GitHub 24-hour database consistency incident

GitHub experienced its longest-ever incident, with degraded service for over 24 hours, as engineers worked to safely reconcile inconsistent data between two data centers.

2018-10-21
When it happened
Technology
Sector
#182 of 300
Ranked by documented impact
01 — What Happened

The damage was public. The root cause was preventable.

GitHub experienced its longest-ever incident, with degraded service for over 24 hours, as engineers worked to safely reconcile inconsistent data between two data centers.

Technology
Sector affected
2018-10-21
Date of the event
#182
Rank in the 300 Software Failure Case Studies
2
Distinct root-cause clauses identified below
02 — The Root Cause

What the software actually got wrong

A brief network partition caused GitHub's database clusters in two data centers to each continue accepting writes independently; reconciling the resulting conflicting data without losing any user information required a lengthy, careful manual process rather than an automatic recovery.

01Root Cause

A brief network partition caused GitHub's database clusters in...

What Happened

A brief network partition caused GitHub's database clusters in two data centers to each continue accepting writes independently

How Requs AI Catches This

Requs AI Edge Case flags this exact pattern at the requirements and architecture stage — before a single line of code implementing it exists — so the assumption behind it gets challenged while it is still cheap to fix.

02Root Cause

Reconciling the resulting conflicting data without losing any user...

What Happened

reconciling the resulting conflicting data without losing any user information required a lengthy, careful manual process rather than an automatic recovery

How Requs AI Catches This

Requs AI Software FMEA traces this failure mode back to the system-level hazard it feeds, tagging it against the Common Defect Enumeration so it surfaces in review instead of in the field.

03 — How This Gets Caught Before It Happens

Beyond code coverage and "shall" testing

Root causes like this one rarely show up in code coverage or requirements-compliance testing, because nobody wrote a requirement anticipating the specific edge case that broke. Requs AI Edge Case and Requs AI Software FMEA are built to surface exactly this class of overlooked failure mode — before the software is written.

Requs AI Edge Case

Surfaces this before code exists

Identifies edge cases like this one at requirements and architecture time, using the Common Defect Enumeration to catalog failure patterns seen across hundreds of real-world software failures — including this one.

Requs AI Software FMEA

Connects the failure mode to the hazard

Traces this class of root cause directly to the system-level hazard it can produce, so a defect pattern like this one gets flagged during design review instead of after it ships.

Find the overlooked root causes before they ship.

Schedule a demonstration, or explore how Requs AI Edge Case and Software FMEA use the Common Defect Enumeration.