TN-R5-005 — Drive Order Ambiguity and Stripe Misalignment
0. Purpose and Scope
This note explains how incorrect member order silently breaks RAID 5 reconstruction.
1. Member Order as a Parity Dependency
Parity math depends on:
- Disk sequence
- Stripe rotation alignment
- Block offsets
Correct disks in the wrong order produce incorrect results.
2. Common Causes of Order Ambiguity
- Controller replacement
- Foreign config imports
- Multiple drive removals
- Reboots during degraded states
3. Why Errors Appear Subtle
Arrays may:
- Mount successfully
- Appear intact
- Show corrupted or empty files
Parity still “works” — it just maps incorrectly.
4. Recovery Implication
Member order must be reconstructed logically before any rebuild or parity operation.