A RAID 60 array that goes corrupt immediately after a drive swap is not experiencing a drive problem — it’s experiencing a logic-layer break.
When a RAID 60 array becomes unreadable right after replacing a disk, one of the RAID-6 groups failed its internal validation check.
And because RAID 60 stripes across groups, one failed group poisons the entire virtual disk.
This failure looks sudden.
It isn’t.
It was building silently long before the drive was removed.
1. What Actually Broke When You Swapped the Drive
Replacing a drive in RAID 60 triggers:
- Foreign-config comparison
- Parity-domain checkpointing
- Stripe-map verification
- Sequence and timestamp comparison
If any one of these checks fails, the controller does one of four things:
- declares “corrupt metadata”
- drops the entire virtual disk offline
- reports wrong-sized LUNs
- shows all disks as “good” while refusing to assemble the array
This is normal behavior.
It is a safety lock — not a failure.
2. The Real Cause: Group Mismatch That Existed Before the Swap
Swapping the drive did not cause the corruption.
It merely revealed the corruption.
The underlying problem almost always began earlier:
A. One RAID-6 group was ahead by several writes
Group A may have committed write #20, #21, #22
while Group B only committed write #20.
B. A prior partial rebuild overwrote valid parity
A rebuild that was attempted weeks or months ago may have:
- written partial parity
- truncated a stripe
- updated only one group’s metadata
This eventually forces the controller to fail the whole array on the next drive event.
C. A silent parity mismatch existed undetected
No SMART errors.
No warnings.
But internally — parity math was invalid.
D. Removing the disk forced a mandatory parity check
This is the hidden landmine.
When you swap a drive, the controller must evaluate:
- which group is correct
- which parity domain is valid
- which offsets line up
If the math doesn’t match across both groups, the controller:
refuses to assemble the array, even with all disks good.
3. Why RAID 60 Fails as a Whole When One Group Breaks
RAID 60 is not one array.
It is two RAID-6 arrays masquerading as one RAID-0 stripe.
If either group becomes untrustworthy, the RAID 0 layer cannot safely:
- accept writes
- rebuild parity
- determine truth
- mount the filesystem
This is why you see:
- “Disk Missing After Swap” even though all disks show GOOD
- “Wrong Group ID”
- “Virtual Disk Missing”
- sudden unreadable volumes
- files showing wrong sizes
It’s not a drive problem.
It’s a math problem.
4. Symptom → Explanation → Correct Action
SYMPTOM 1 — Array Immediately Drops Offline After the Swap
Explanation: Foreign-config mismatch found across groups
Correct Action: Freeze state + clone before any controller action
SYMPTOM 2 — Controller Sees All Disks but No Virtual Disk
Explanation: Stripe-map inconsistency collapsed the RAID 0 layer
Correct Action: Reconstruct groups individually in virtual mode
SYMPTOM 3 — Mount Attempt Fails (Windows, Linux, VMware)
Explanation: Parity-domain mismatch invalidates group order
Correct Action: Determine which group is “truth source”
SYMPTOM 4 — Rebuild Attempts Fail Instantly
Explanation: Metadata generations disagree
Correct Action: Extract & compare per-disk sequence frames
SYMPTOM 5 — Foreign Config Not Accepting
Explanation: One group’s metadata was overwritten by a partial rebuild
Correct Action: Manual parity-domain reconciliation
5. How ADR Recovers RAID 60 After Corruption
ADR’s RAID Inspector™ performs a full logic-layer rebuild without touching the original drives.
1 — Per-Drive Metadata Extraction
We analyze each disk’s sequence, commit maps, timestamps, and parity frames.
2 — Independent Virtual Reconstruction of Both RAID-6 Groups
Each group is rebuilt in isolation to find parity-domain drift.
3 — Stripe and Offset Comparison
We identify the exact divergence point.
4 — Parity-Domain Arbitration (“Truth Selection”)
We determine which group contains the authoritative writes.
5 — Controlled, Mathematical Realignment
We reassemble the RAID 60 structure using virtualized components.
6 — Filesystem Repair (Only After Math Is Trusted)
This is why ADR succeeds where others fail.
We treat RAID 60 as the dual-array system it is — not a single block device.
Diagnostic Overview
- Device: RAID 60 array (dual RAID-6 groups striped under RAID 0)
- Observed State: Array corrupt or unreadable directly after drive swap
- Likely Cause: Pre-existing group mismatch revealed during parity validation
- Do NOT: Force rebuild, initialize, or re-import foreign configs
- Recommended Action: Offline imaging, per-group metadata extraction, parity-domain comparison, safe realignment before reconstruction
RAID Triage Center – RAID 60 Triage – RAID 60 Technical Notes