When RAID fails, the controller is often the first—and most overlooked—suspect. The truth is, many data loss events begin not with a disk failure, but with how the controller interprets what it sees. A misread configuration, a stale cache, or a corrupted foreign import can turn a healthy array into a chain of errors that no software can safely guess back into place.
At ADR, we analyze every array at the controller logic level before any rebuild or clone attempt. Whether your system uses Dell PERC, HP Smart Array (ADG), LSI / MegaRAID, or complex environments like NetApp RAID-DP, Synology mdadm hybrids, or Drobo BeyondRAID—each platform writes its own metadata, parity offsets, and recovery pathways. Understanding those differences is what prevents a bad import from becoming a permanent loss.
Precision Starts at the Controller Layer
Every controller family encodes array maps differently:
- Dell PERC: prone to “Foreign Config” events, stale VD tables, and misleading “Offline Virtual Disk” flags.
- HP Smart Array (ADG): caching and battery-backed write issues can mask an array’s last consistent state.
- LSI / MegaRAID: known for ambiguous virtual-drive import prompts that can overwrite parity tables.
- NetApp RAID-DP / RAID-TEC: dual or triple parity events require logical reconstruction beyond standard RAID-6 logic.
- Synology / QNAP: combine mdadm software layers with proprietary volume headers—making imports unpredictable.
- Drobo BeyondRAID: uses proprietary translation layers that can collapse when the enclosure firmware fails.
Why Controller-Level Forensics Matter
A RAID array is not just disks—it’s an active conversation between firmware, cache, and metadata. When that communication breaks, traditional “RAID recovery tools” only see fragmented storage. ADR’s approach reconstructs the controller’s intent—the way it actually wrote data—before touching a single block. This controller-aware process allows us to recover arrays other labs declare “unrecoverable.”
Each controller type has its own triage method and risk profile. The pages below outline the most common failure modes, what not to do (like clearing or importing foreign configs), and what ADR’s controller-level inspection can reveal before irreversible steps are taken.