RAID 5 Data Recovery

Swindon Data Recovery: The UK’s Premier RAID 5, 6 & 10 Recovery Specialists

For 25 years, Swindon Data Recovery have been the UK’s leading experts in complex RAID data resurrection, specialising in the intricate architectures of RAID 5, RAID 6, and RAID 10. Our dedicated RAID engineers possess an unrivalled, deep-seated understanding of parity calculations, striping algorithms, and nested array structures. We have successfully recovered data from the most catastrophic multi-drive failures for clients ranging from home users to government departments and multinational corporations. Leveraging a vast inventory of advanced hardware and proprietary software tools, we maximise recovery success where others fail. All engagements begin with a free, no-obligation diagnostics report.

Our 25-Year Legacy of Complex RAID Expertise
A quarter-century in the data recovery industry has provided us with an unparalleled forensic understanding of the evolution of RAID technology. We have navigated every iteration of RAID 5, from early hardware controllers with proprietary XOR stripe calculations to modern software implementations. Our experience with RAID 6, with its dual parity complexity, and the nested mirroring and striping of RAID 10, is built upon thousands of successful recovery cases. This historical corpus of knowledge—encompassing firmware libraries, controller profiles, and file system behaviours—allows us to rapidly diagnose and rectify failures that are insurmountable for less experienced labs.

Comprehensive Device & Brand Support

We recover data from all RAID 5, 6, and 10 configurations, from small 3-disk RAID 5 arrays to massive 32-disk RAID 60 (RAID 6+0) setups, including:

• Hardware RAIDs: Dell PERC, HPE Smart Array, Adaptec, LSI, IBM ServeRAID.

• Software RAIDs: Windows Storage Spaces, Linux MDADM, ZFS RAID-Z/Z2.

• NAS Systems: All brands and models, supporting SHR (Synology Hybrid RAID).

• Rack Servers & SANs: Complex multi-bay enclosures and enterprise storage area networks.

Top 15 Selling NAS External Drive Brands & Popular Models in the UK:

1. Synology: DiskStation DS923+ (RAID 5 capable), DS1522+, RS1221+

2. QNAP: TS-464, TVS-872X, TS-1655

3. Western Digital (WD): My Cloud EX4100, My Cloud PR4100

4. Seagate: IronWolf 4-bay NAS, BlackWolf 8-bay NAS

5. Netgear: ReadyNAS 434, ReadyNAS 5312X

6. Buffalo Technology: TeraStation 3410DN, 51210RH

7. Drobo: Drobo 5N2, Drobo 8D

8. Asustor (ASUS): AS5304T, Lockerstor 6 Gen2 (AS6706T)

9. Thecus: N8850, W6810

10. TerraMaster: F4-423, T9-450

11. LaCie: 12big Rack Thunderbolt 3

12. Lenovo: PX12-450R, IX4-300D

13. Promise Technology: Pegasus32 R8, R8i

14. ZyXEL: NAS542, NAS572

15. D-Link: DNS-345

Top 15 Selling RAID 5 & 10 Capable Servers & Popular Models in the UK:

1. Dell EMC: PowerEdge R750xs, R740xd2

2. Hewlett Packard Enterprise (HPE): ProLiant DL380 Gen11, DL360 Gen11

3. Lenovo: ThinkSystem SR650, SR630 V2

4. Cisco: UCS C240 M7 Rack Server

5. Supermicro: SuperServer 6049P-E1CR90H, 6029P-E1CR90H

6. Fujitsu: PRIMERGY RX2540 M7, RX4770 M5

7. Hitachi (HGST): Hitachi Compute Blade 2000

8. IBM: Power System S1022, FlashSystem 5200

9. Acer: Altos R380 F3

10. ASUS: RS720-E10-RS12U, ESC4000-E10

11. Intel: Intel Server System R2000WF family

12. Huawei: FusionServer 2288H V5, 5288 V5

13. Oracle: Sun Server X4-4, SPARC Servers

14. Inspur: Inspur NF5280M6, NF5180M6

15. NettApp: A250, A400

In-Depth Technical Recovery: Problems & Processes for RAID 5/6/10

The complexity of RAID 5, 6, and 10 requires a sophisticated understanding of data distribution and redundancy. Below is a detailed breakdown of common issues and the advanced recovery processes we employ in our lab.

Top 25 Software RAID Errors We Recover From

1. Multiple Drive Failures Exceeding Redundancy: In RAID 5, a second drive fails; in RAID 6, a third drive fails, making the array irrecoverable by standard means.

   • Technical Recovery: We create full sector-by-sector images of all remaining drives, including the failed ones (after physical repair if necessary). Using advanced tools like UFS Explorer RAID Recovery or R-Studio, we perform a parametric analysis to determine the original RAID parameters (stripe size, disk order, parity rotation). We then construct a virtual RAID, using the surviving drives and the partial data from the “failed” drives. By strategically treating the most damaged areas as “missing,” we can often reconstruct a coherent file system, leveraging the remaining parity data to fill critical gaps.

2. Parity Corruption and Mismatch: The parity blocks across the array become inconsistent with the data blocks, leading to data corruption.

   • Technical Recovery: We analyse the raw data blocks and parity blocks to identify the extent of the corruption. Our engineers manually locate filesystem metadata areas (MFT for NTFS, inode tables for ext4) that are often critical. We then perform a selective parity rebuild, focusing on reconstructing these metadata structures first. This allows the filesystem to be mounted, after which user data can be extracted, often bypassing the corrupted parity in non-critical data regions.

3. Failed Rebuild Process on a Degraded Array: The system attempts a rebuild onto a new drive but fails mid-process, often due to an unrecoverable read error (URE) on a remaining drive, corrupting the new drive and potentially the array’s structure.

   • Technical Recovery: This process is halted immediately. We image all drives. The key is to ignore the partially rebuilt new drive and instead work with the original, pre-failure set of drives. We virtualise the array in its degraded but stable pre-rebuild state. Using hardware imagers like the DeepSpar Disk Imager, we can often read past the URE that caused the failure, allowing us to extract a clean, complete image of the degraded array for final data reconstruction.

4. Accidental Reinitialisation or Formatting: The entire array is mistakenly reinitialised, destroying the RAID metadata and partition information.

   • Technical Recovery: Reinitialisation typically overwrites only the RAID metadata area at the start of each drive and the partition table. The user data stripes and parity often remain intact. We perform a deep scan of the raw drives to locate residual RAID configuration signatures and file system fragments. By analysing the cyclic patterns of data and parity, we can mathematically deduce the original RAID parameters (stripe size, disk order) and reassemble the array virtually, allowing file system recovery tools to operate on the logical volume.

5. RAID Member Offline/Removal and Reordering: One or more drives are accidentally disconnected or reordered, causing the controller or OS to see the array as invalid.

   • Technical Recovery: We image all drives. The recovery software then performs a combinatorial analysis, testing millions of potential disk orders, start offsets, and stripe sizes against known file system signatures. Once the correct geometry is identified, the virtual array assembly is validated by checking for consistency in critical file system structures, confirming the correct configuration before data extraction.

6. File System Corruption on Top of the RAID Volume.

7. Metadata Corruption (MDADM superblock, Storage Spaces database).

8. Driver or OS Update Causing Array Inaccessibility.

9. Bad Blocks in the RAID Metadata or Parity Area.

10. Unclean Shutdown Leading to “Split-Brain” or Journal Corruption.

11. Software Bug During Consistency Check or Scrubbing.

12. LVM (Logical Volume Manager) Corruption on a Software RAID.

13. Resource Exhaustion Causing Write Hole (lack of battery backup).

14. Snapshot Corruption on a Virtualised RAID Volume.

15. Configuration Import/Export Failure.

16. Security Software or Ransomware Encryption.

17. Incorrect Drive Replacement Procedure.

18. GPT/MBR Partition Table Corruption on the RAID Volume.

19. Volume Deletion within the Operating System.

20. File System Mounting Errors Despite Array Being “Healthy”.

21. ZFS Pool Corruption (RAID-Z/Z2).

22. Synology Hybrid RAID (SHR) Configuration Loss.

23. Storage Spaces Parity Virtual Disk Failure.

24. Memory Dump on the RAID Volume Overwriting Critical Structures.

25. Journaling File System (ext4, NTFS) Failures.

Top 25 Mechanical/Electronic/Hardware RAID Errors We Recover From

1. RAID Controller Failure with No Configuration Backup: The physical controller card fails, and its configuration (stripe size, disk order, etc.) is lost.

   • Technical Recovery: We source an identical donor controller. Crucially, we use tools like PC-3000 to read the vendor-specific configuration metadata that is often written to the last sectors of each member drive. If this is corrupt, we perform a parametric analysis, as with software RAIDs, but with the added complexity of accounting for the controller’s specific XOR algorithm and potential NVRAM cache data loss. We manually reconstruct the configuration to build a virtual assembly.

2. Concurrent Multiple Drive Failures (e.g., from a power surge): Multiple drives in the array suffer electronic (PCB) failure simultaneously.

   • Technical Recovery: Each failed drive undergoes a meticulous PCB repair or swap, which includes transferring the unique adaptive firmware from the patient drive’s ROM to the donor PCB using an EEPROM programmer. Once all drives are electronically functional, they are imaged in a controlled manner. The images are then used to reconstruct the array virtually, as the original hardware environment (the failed controller) is often untrustworthy.

3. Unrecoverable Read Error (URE) During Rebuild: A single drive fails, but during the rebuild, a second drive encounters a bad sector, halting the process and crashing the array.

   • Technical Recovery: This is a classic RAID 5 failure scenario. We image all drives, including the failed one (after physical recovery if needed). Using the DeepSpar Disk Imager, we employ its hardware-based bad sector recovery functions to aggressively attempt to read the problematic sector. If the physical media is damaged, we may use advanced techniques like reading the sector at a reduced spin speed. Once the data from the bad sector is retrieved, it is patched into the drive image, allowing the rebuild process to be completed successfully in our virtual environment.

4. Firmware Corruption on a Single Drive Causing Array Degradation: A member drive develops firmware corruption, making it intermittently disappear from the array or report incorrect capacity.

   • Technical Recovery: We use a PC-3000 system to diagnose and repair the firmware on the affected drive. This involves accessing the drive’s Service Area (SA) on the platters to repair corrupted modules such as the translator, system files, or zone configuration. Once the drive’s firmware is stabilised and its true, correct capacity is restored, it can be reliably imaged and reassembled with the other members in the virtual RAID.

5. Backplane Failure Causing Corruption on Multiple Drives: A faulty backplane in the server or NAS corrupts data as it is written to or read from multiple drives.

   • Technical Recovery: This is a complex failure that often results in “pseudo” drive failures. We first diagnose and rule out backplane issues. We then image all drives. The analysis involves comparing data and parity blocks across the array to identify the corruption pattern. By understanding the pattern (e.g., corruption on specific sectors from specific ports), we can algorithmically correct the errors in the disk images before performing the final virtual RAID assembly and data extraction.

6. Read/Write Head Stack Failure on One or More Drives.

7. Spindle Motor Seizure on a Critical Array Member.

8. PCB Failure (Voltage Regulator, TVS Diode, Controller IC).

9. Bad Sectors (Media Degradation) on Multiple Drives.

10. Controller Battery Backup Unit (BBU) Failure Leading to Write-Hole Corruption.

11. NVRAM Corruption on the RAID Controller.

12. Failed Drive Rebuild on a Replacement Drive.

13. S.M.A.R.T. Attribute Overflow Forcing a Drive Offline.

14. Thermal Calibration Crash (TCC) on Modern High-Capacity Drives.

15. Physical Media Damage (Scratched Platters) from a Head Crash.

16. Power Surge Damaging Controller and Multiple Drive PCBs.

17. Stiction (Platters Stuck Together) Preventing Drive Spin-Up.

18. Servo Wedge Damage Preventing Accurate Head Positioning.

19. Degraded Read Performance Causing Controller Timeouts.

20. Cable/Connector Damage Causing Intermittent Link Loss.

21. Water/Fire/Physical Damage to the Entire Array Unit.

22. Preamp Failure on the Head Assembly.

23. Encoder/Decoder (Read Channel) Failure on the Drive PCB.

24. Write Inhibit Mode Activation.

25. SAS Phy Layer Failure on Enterprise Drives.

Top 25 Virtual/File System RAID Errors We Recover From

1. Corruption within a ZFS RAID-Z (Z1) or RAID-Z2 (Z2) Pool: Damage to the ZFS uberblocks, Meta Object Set (MOS), or Data Configuration Store (DCS).

   • Technical Recovery: We use the zdb (ZFS Debugger) tool to perform a forensic analysis of the pool. We locate previous, valid transaction groups (txgs) by scanning for backup uberblocks. By instructing ZFS to import the pool from a specific, older uberblock, we can effectively roll back the pool’s state to a point before the corruption occurred, allowing for data extraction.

2. VHD/VHDX File Corruption on a Hyper-V Virtual Machine stored on a RAID: The container file’s internal metadata, such as the dynamic disk block allocation table (BAT), is damaged.

   • Technical Recovery: We use hex editors and utilities like vhdtool to parse the VHD/X structures. We repair the VHD header and reconstruct the BAT by analysing the raw sector data within the file. This remaps the virtual sectors to the correct physical sectors on the underlying RAID, allowing the VHD/X to be mounted and the guest file system to be accessed.

3. QTS (QNAP) File System Corruption on a RAID 5 SHR Volume: Corruption of the proprietary LVM and file system layers that QNAP uses on top of MDADM.

   • Technical Recovery: This is a multi-layered recovery. We first must correctly reassemble the underlying Linux MDADM RAID 5 array. Then, we must navigate and repair the QNAP-specific LVM and file system structures on top of it. This involves reverse-engineering QNAP’s on-disk format to locate and repair superblocks, inode maps, and directory entries, often using custom scripts alongside advanced recovery software.

4. Btrfs File System Corruption on a RAID 5/6 Array: Damage to critical B-trees like the Chunk Tree, Root Tree, or File System Tree.

   • Technical Recovery: Btrfs is a self-validating filesystem. We use btrfs-restore in a read-only mode. For severe corruption, we manually parse the B-trees, searching for valid backups of critical roots (ROOT_ITEM, ROOT_REF). By identifying a consistent root node, we can reconstruct a coherent view of the filesystem, leveraging the copy-on-write nature of Btrfs to find older, undamaged versions of metadata.

5. ext4 Journal Corruption on a Software RAID 5: The journal (jbd2) becomes corrupt, causing the kernel to refuse to mount the filesystem.

   • Technical Recovery: We attempt to recover by replaying a clean journal from a backup superblock. If the journal is unrecoverable, we use debugfs to manually navigate the file system using direct inode pointers, bypassing the damaged journal. Alternatively, we can run a raw scan on the assembled RAID volume to recover data based on file signatures, a process known as file carving.

6. VMFS (VMware) Datastore Corruption on an underlying RAID 5/6 LUN.

7. Hyper-V VHD Set (VHDS) Corruption for Guest Clusters.

8. Thin Provisioning Metadata Corruption on a Virtualised RAID.

9. Snapshot Delta File Corruption on a RAID Volume.

10. Deduplication Table Corruption.

11. LUKS Encryption Header Damage on a Software RAID.

12. APFS (Apple File System) Container Corruption on a RAID.

13. ReFS (Resilient File System) Corruption on a Storage Spaces RAID.

14. XFS Allocation Group Corruption on a Large RAID Volume.

15. NTFS $MFT Mirror Mismatch on the RAID Volume.

16. Dynamic Disk Database Corruption (Windows) on a RAID 5.

17. File System Journal Overflow.

18. Metadata-only RAID 5/6 Split-Brain.

19. QNAP LVM-thick Provisioning Corruption.

20. Btrfs RAID 1c/1c3 Profile Mismatch.

21. Storage Spaces Virtual Disk Corruption.

22. ZFS Intent Log (ZIL) Corruption.

23. Virtual Disk Consolidation Failure (VMware).

24. QNAP QuLog Database Corruption.

25. File System Quota Database Corruption.

Contact Your Expert RAID 5, 6 & 10 Engineers Today

Our 25 years of specialised expertise in complex parity and nested RAID systems, combined with our state-of-the-art lab in Swindon, ensures the highest possible chance of a successful recovery from any RAID 5, 6, or 10 failure. We operate with strict confidentiality and a commitment to providing the best value in the UK.

Do not attempt risky rebuilds or run destructive utilities. Contact our specialist Swindon RAID engineers immediately for a free, detailed diagnostics assessment.