Rebuild Won’t Start After Second Drive Swap

When the Safety Net Refuses to Catch You — RAID’s Pause for Protection

You replaced the failed drive, watched LEDs flicker, and waited for the rebuild prompt — nothing.
The controller sits silent, the array idle.
It feels like a failure, but it’s really a stand-down: the system refusing to risk your data until it’s sure of its math.
Understanding that hesitation can save the array you still have.

What You See

Controller detects replacement drive but no rebuild initiates.
Status = Ready / Unconfigured Good, not part of VD.
Foreign Config Detected on inserted drive.
Event log shows Parity Inconsistent or Invalid RAID State.
System may show array as Offline but intact in BIOS.

Why It Happens

Controller requires verified parity consistency before new rebuild.
Prior rebuild aborted, leaving metadata in a transient state.
Different firmware or block size on the replacement drive.
Cache policy set to write-back without battery learn completed.
Previous drive drop marked two members as suspect, blocking auto start.

What NOT To Do

Do not force rebuild through CLI or BIOS.
Do not clear foreign configs on the entire set.
Do not power-cycle repeatedly hoping it starts.
Do not mix different capacity replacements without re-initial mapping.
Do not reset NVRAM before exporting the controller state.

What You CAN Do

Check controller policy logs for parity verification requirements.
Validate each member’s metadata epoch before re-adding.
Use diagnostic mode to compare array layout signatures.
Export current configuration to USB or NVRAM dump.
Consult ADR triage guide to verify safe rebuild start conditions.

Diagnostic Overview

Array Type: RAID 6 — Dual Parity Set
Controller State: Replacement Inserted / Rebuild Idle
Likely Cause: Metadata Mismatch or Unverified Parity Set
Do NOT: Force Rebuild or Clear Foreign Config Before Validation
Recommended Action: Validate Member Signatures, Export Logs, Follow ADR Triage Flow