SYMPTOM
“RAID 50 offline — one stripe group isn’t showing up.”
Your RAID 50 volume has gone offline or is showing as degraded. In your controller interface or system logs, one of the mirrored stripe groups is completely absent or showing all disks as foreign or failed.
You may have:
- One stripe group fully offline
- Foreign or “unconfigured bad” drives in one half
- Total loss of access to the RAID volume
WHAT’S REALLY HAPPENING
RAID 50 is a nested configuration: multiple RAID 5 sets striped together. If one full RAID 5 stripe group is lost, the entire RAID 50 volume fails. But what’s critical to understand is that:
- This isn’t just a multiple-drive failure. It’s a full segment failure in a nested array — and controller behavior here varies dramatically.
- If the drives show as “foreign” or unresponsive, your controller may be suppressing them due to a dirty shutdown, aging drives, or firmware mismatch.
- You may still have readable data on the missing stripe group — but a rebuild or forced import could destroy that.
WHAT NOT TO DO
❌ Don’t force a rebuild on the visible half
❌ Don’t import a foreign config without imaging first
❌ Don’t rely on controller auto-recovery — it’s blind to parity mismatch
Tools like MegaRAID, Dell PERC, or Intel RST often offer to rebuild, import, or “make good” drives. If you accept these options prematurely:
- The array could rebuild based on stale parity
- Data overlap or timestamp mismatch may get cemented into new writes
- Logs will be wiped — closing the door on safe recovery
WHEN TO ESCALATE
Call us immediately if:
- You’re missing 2+ drives from the same stripe group
- One half of the RAID 50 appears completely unmounted or shows as “offline” or “foreign”
- The rebuild suggestion appears without confirmation of correct drive order or parity integrity
This is not a traditional RAID 5 failure — and generic recovery labs often misdiagnose it.
With RAID Inspector™, powered by IntelliCore Logic™, ADR uses low-level SMART trace analysis and cross-array validation to confirm whether:
- The missing stripe group is still intact
- Parity is readable across the group
- Drive order and interleave were preserved
TRUST POINT
Before you lose it for good — let JeannieLite™ take a look.
✅ Lightweight Triage
✅ No install required
✅ Full RAID map visual in under 60 seconds
🟦 Run JeannieLite RAID Diagnostic Tool Now