RAID 60 Degraded After Power Loss: Preserve Both RAID 6 Groups
A power event can leave RAID 60 degraded because a member became unavailable, a controller or enclosure path changed, cached writes were interrupted, or one lower RAID 6 group is no longer presented as expected. The complete compound layout must be preserved before another operation changes it.
Do not start a rebuild, force a member online, import configuration, or recreate the virtual disk. Record both group states and every member first.
What this condition means
RAID 60 stripes data across two or more RAID 6 groups. The controller must identify the members and geometry of each lower group and then assemble the top-level stripe correctly.
A degraded label does not identify the cause by itself. The event may involve a genuinely unreadable member, timeouts, power or backplane trouble, changed metadata, controller cache, or a lower group that the controller no longer trusts.
What to record
- Server, controller, enclosure, firmware, and expected RAID 60 capacity
- Total member count and the displayed membership of each RAID 6 group
- Bay, serial number, size, and current status of every drive
- Cache, battery, capacitor, power, and controller event messages
- Every reboot, replacement, import, force-online, rebuild, or repair already attempted
What not to do
- Rebuild simply because the controller recommends it
- Clear or import configuration before documenting both groups
- Move members between bays while testing
- Initialize a missing or newly presented virtual disk
- Run filesystem repair on an unvalidated compound reconstruction
How ADR evaluates it
ADR reviews the controller report, member order, drive sizes, and power-event history, then protects any drive that cannot be read reliably.
Each lower RAID 6 group is reconstructed before the stripe joining the groups is tested. Recovered data is written to separate destination storage.
What happens next
ADR can begin from the preserved member set without asking the failed server to mount the volume. The next decision is whether the drives can be accessed safely onsite or require protected imaging elsewhere.