Raid 5 Recovery

RAID 5 Data Recovery

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Our experts have extensive experience recovering data from RAID servers. With 25 years experience in the data recovery industry, we can help you securely recover your data.
Raid 5 Recovery
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Swansea Data Recovery: The UK’s No.1 RAID 5, 6 & 10 Recovery Specialists

For 25 years, Swansea Data Recovery has been the UK’s leading specialist in recovering data from complex redundant arrays. RAID 5 (striping with distributed parity), RAID 6 (striping with double distributed parity), and RAID 10 (mirrored stripes) offer robust performance and fault tolerance, but their complexity introduces unique failure modes that can lead to catastrophic data loss. We provide professional recovery services for all types of these arrays, from small 3-disk RAID 5 setups to massive 32-disk enterprise RAID 6 configurations, across all hardware controllers, software implementations, and NAS devices.

Supported Systems & NAS Devices

Top 15 NAS Brands & Popular Models for RAID 5/6/10 in the UK:

  1. Synology: DiskStation DS1621+, DS1821+, DS3622xs+

  2. QNAP: TVS-872X, TS-1635AX, TS-h1290FX

  3. Western Digital (WD): My Cloud Pro Series PR4100, PR2100

  4. Buffalo Technology: TeraStation 5120Rh, 3410DN

  5. Netgear: ReadyNAS RN626X, RN424

  6. Asustor: AS6508T, AS7110T

  7. Thecus: N8850, N12000V

  8. Terramaster: D8-332, F8-422

  9. Dell EMC: PowerVault NX3240

  10. HP: ProLiant Storage Server

  11. Lenovo: ThinkSystem DE Series

  12. Seagate: BlackArmor NAS 440

  13. Infortrend: EonStor DS 1024D

  14. Promise Technology: VTrak E610sD

  15. LaCie: 12big Rack 4U

Top 15 RAID 5/6/10 Server Brands & Models:

  1. Dell EMC: PowerEdge R740xd, R750xa, PowerVault MD3460

  2. Hewlett Packard Enterprise (HPE): ProLiant DL380 Gen10, StoreEver MSL2024

  3. IBM/Lenovo: ThinkSystem SR650, ST250

  4. Supermicro: SuperStorage 6048R-E1CR24N, 2028U-TR4

  5. Cisco: UCS C240 M5 SD

  6. Fujitsu: PRIMERGY RX2530 M5, RX4770 M1

  7. Oracle: Sun Fire X4270 M3, ZFS Storage Appliance

  8. Hitachi Vantara: VSP E Series, HUS VM

  9. NetApp: FAS Series (FAS2600, AFF A250)

  10. Intel: Server System S2600WF

  11. Acer: Altos R380 F2

  12. ASUS: RS720-E9-RS12U

  13. Promise Technology: Vess R3660

  14. Areca: ARC-8050T3

  15. QNAP: TS-EC2480U R2

Top 25 RAID 5, 6 & 10 Errors & Our Technical Recovery Process

1. Multiple Simultaneous Drive Failures in RAID 5

  • Summary: Two or more drives fail in a RAID 5 array, exceeding its single-drive fault tolerance and causing array failure.

  • Technical Recovery: We create physical images of all drives, including failed ones (via cleanroom recovery if needed). Using virtual RAID reconstruction software, we perform parity inversion calculations. For each unrecoverable sector from the second failed drive, we use the formula: Failed_Drive_Data = Surviving_Drive1_Data XOR Surviving_Drive2_Data XOR Parity_Data. This allows mathematical reconstruction of missing data by solving the XOR equation across the stripe set.

2. Triple Drive Failure in RAID 6

  • Summary: Three drives fail in a RAID 6 array, exceeding its two-drive fault tolerance through Reed-Solomon codes or dual parity.

  • Technical Recovery: After imaging all drives, we employ Galois field algebra to reconstruct data. Unlike RAID 5’s simple XOR, RAID 6 uses polynomial equations: P = D₁ + D₂ + D₃ + ... + Dₙ and Q = a¹D₁ + a²D₂ + a³D₃ + ... + aⁿDₙ. By solving these simultaneous equations using the surviving drives’ data, we can recover from two complete drive failures, and partially recover data where the third failure overlaps.

3. Failed Rebuild Process on Degraded Array

  • Summary: A rebuild process initiated after a single drive failure fails due to encountering bad sectors on surviving drives or a second drive failure during rebuild.

  • Technical Recovery: We create pre-rebuild images of all drives. Using staleness analysis, we identify which sectors were being written during the failed rebuild. We then perform a virtual rollback by reconstructing the array state before rebuild initiation, using the original failed drive’s data (recovered via physical means) combined with the pre-rebuild state of surviving drives.

4. RAID Controller Metadata Corruption

  • Summary: The controller’s configuration metadata (stored in NVRAM or on disk) becomes corrupted, losing critical parameters like stripe size, disk order, and parity rotation.

  • Technical Recovery: We image all drives and perform combinatorial parameter analysis. Our software tests thousands of combinations of stripe sizes (4KB-1MB+), disk orders, and parity directions (left/right symmetric/asymmetric, forward/backward dynamic). The correct configuration is identified when file system structures (NTFS $MFT, EXT superblocks) align perfectly across calculated stripe boundaries.

5. URE (Unrecoverable Read Error) During Rebuild

  • Summary: A single uncorrectable read error on a surviving drive during RAID 5 rebuild causes the entire rebuild process to abort.

  • Technical Recovery: We use hardware imagers with adaptive read techniques – multiple read attempts with progressively slower timing and reduced retry thresholds. For the specific sector causing the URE, we attempt reconstruction using XOR parity from the corresponding stripe: Bad_Sector = (All_Other_Data_Sectors_In_Stripe) XOR Parity_Sector.

6. RAID 10 Mirror-Set Failure

  • Summary: Multiple drive failures occur within the same mirror set of a RAID 10 array, breaking the stripe and causing data loss.

  • Technical Recovery: We treat this as multiple independent RAID 1 recoveries. Each mirror set is analysed separately. For broken mirror sets, we perform physical recovery on failed drives. The surviving mirror sets provide complete data for their stripes, while recovered mirror sets are reassembled using standard RAID 1 techniques before the overall stripe set is reconstructed.

7. Partial Write/Write Hole Corruption

  • Summary: Power loss during write operations leaves some drives updated while others contain old data, creating parity inconsistencies.

  • Technical Recovery: We analyse parity blocks versus data blocks across all drives. Inconsistent stripes are identified where Parity != D₁ XOR D₂ XOR ... XOR Dₙ. We then use file system journal replay (NTFS $LogFile, EXT journal) to roll back incomplete transactions to the last consistent state before the power loss event.

8. Accidental Array Reinitialization

  • Summary: The entire array is mistakenly reinitialized, overwriting RAID metadata and potentially partition tables.

  • Technical Recovery: We search each drive for backup RAID metadata typically stored at sector 0 or the end of the drive. For manufacturers like Adaptec and LSI, we parse their specific metadata structures (superblocks) to recover original parameters. If metadata is destroyed, we perform raw carving across all drives, using known file signatures to reconstruct data.

9. Drive Removal and Incorrect Reordering

  • Summary: Drives are physically removed and reinserted in incorrect order, scrambling the array sequence.

  • Technical Recovery: We test all possible drive order permutations (n! possibilities). The software identifies the correct order by verifying data continuity across stripe boundaries and validating checksums of known file system structures at calculated intervals.

10. Bad Sectors Distributed Across Multiple Drives

  • Summary: Multiple drives develop bad sectors in different locations, creating a distributed pattern of data loss.

  • Technical Recovery: We create consolidated bad sector maps for all drives. Our virtual RAID reconstruction uses a priority system: first attempting reads from primary drives, then using parity reconstruction for affected stripes, and finally employing advanced error correction where multiple drives have errors in the same stripe.

11. Firmware Corruption on Multiple Drives

  • Summary: Firmware issues affect multiple drives simultaneously, often due to bugs or incompatible updates.

  • Technical Recovery: We use technological modes (PC-3000) to bypass corrupted firmware on affected drives. For each drive, we access the service area to repair modules or read user data directly. The recovery process accounts for the temporal nature of the corruption, prioritizing drives based on their last known good state.

12. RAID 5/6 Expansion Failure

  • Summary: The process of expanding array capacity fails or is interrupted, leaving the array in an inconsistent state.

  • Technical Recovery: We recover the pre-expansion RAID metadata and reconstruct the array using original parameters. We then manually complete the expansion process logically in our virtual environment, carefully migrating data to the new layout without risking the original drives.

13. Controller Cache Corruption with BBU Failure

  • Summary: The controller’s battery backup unit fails, leading to loss of cached writes and potential data corruption.

  • Technical Recovery: We analyse write patterns across all drives to identify incomplete write sequences. Using file system journal analysis, we identify and roll back transactions that weren’t fully committed, restoring consistency to the last stable checkpoint.

14. Synchronization Loss in Complex Arrays

  • Summary: The array loses synchronization between components, particularly in nested or complex RAID configurations.

  • Technical Recovery: We deconstruct the array into its fundamental components (RAID 1 sets within RAID 10, or individual RAID 5/6 sets within nested configurations). Each component is recovered independently before being reassembled into the complete logical volume.

15. File System Corruption on RAID Volume

  • Summary: The file system on the logical volume becomes corrupted while the underlying RAID structure remains intact.

  • Technical Recovery: After ensuring proper RAID reconstruction, we perform advanced file system repair. For ZFS, we work with Uberblocks and the ZAP. For NTFS, we repair the $MFT using its mirror. For EXT4, we use journal replay and superblock backups.

16. Viral Encryption on RAID Volume

  • Summary: Ransomware encrypts files on the active RAID volume.

  • Technical Recovery: After RAID reconstruction, we employ ransomware-specific recovery techniques including shadow copy analysis, temporary file recovery, and in some cases, cryptographic analysis of the encryption implementation.

17. Backplane or Enclosure Failure

  • Summary: Physical connectivity issues in the storage enclosure cause multiple drives to appear failed.

  • Technical Recovery: We remove all drives and connect them directly to controlled ports on our forensic workstations. This eliminates backplane issues and allows accurate assessment of each drive’s true health status.

18. Power Surge Damaging Multiple Components

  • Summary: Electrical surge damages multiple drive PCBs and potentially the RAID controller.

  • Technical Recovery: Each damaged PCB undergoes component-level repair with ROM transfer. We systematically replace TVS diodes, fuses, and motor controllers while preserving unique adaptive data from each drive.

19. S.M.A.R.T. Error Cascades

  • Summary: Predictive S.M.A.R.T. errors cause the controller to preemptively drop multiple drives from the array.

  • Technical Recovery: We assess the actual severity of S.M.A.R.T. errors through direct media access. Many predictive errors don’t immediately affect data readability. We create stable images by temporarily disabling certain S.M.A.R.T. features in the drive firmware.

20. Manufacturer-Specific RAID Implementations

  • Summary: Proprietary RAID implementations (Drobo BeyondRAID, Synology SHR) experience unique failure modes.

  • Technical Recovery: We reverse-engineer the proprietary data structures. For Drobo, we parse packet allocation tables. For Synology SHR, we analyse the Linux mdadm and LVM layers to reconstruct the logical volume.

21. Thermal Damage in High-Density Arrays

  • Summary: Overheating in densely packed arrays causes premature media degradation and electronic failures.

  • Technical Recovery: Each affected drive requires individual thermal assessment and stabilization. We use specialized imaging techniques with temperature monitoring and adjusted read strategies for heat-affected media.

22. Rebuild on Wrong Drive

  • Summary: The controller incorrectly identifies a healthy drive as failed and begins rebuilding onto it.

  • Technical Recovery: We immediately image all drives to preserve pre-rebuild state. We then perform binary analysis to identify overwritten sectors and reconstruct original data from parity calculations and surviving drive data.

23. Complex RAID Migration Failure

  • Summary: Migration between RAID levels (e.g., RAID 5 to RAID 6) fails mid-process.

  • Technical Recovery: We recover the original RAID configuration metadata and reconstruct the array in its pre-migration state. We then carefully complete the migration process logically in our virtual environment.

24. ZFS RAID-Z Pool Corruption

  • Summary: ZFS-based RAID (RAID-Z, RAID-Z2) experiences pool corruption due to failed resilvering or memory errors.

  • Technical Recovery: We use ZFS debugging tools (zdb) to analyse Uberblocks and identify the most recent valid transaction group. We then attempt pool import with rollback options to bypass corrupted metadata.

25. Database Corruption on RAID Arrays

  • Summary: Critical database files on the RAID volume become corrupted.

  • Technical Recovery: After RAID reconstruction, we employ database-specific recovery techniques including transaction log analysis, page-level repair, and use of native database utilities to bring the database to a consistent state.

Advanced Technical Capabilities

Parity Mathematics:

  • RAID 5: XOR-based parity P = D₁ ⊕ D₂ ⊕ ... ⊕ Dₙ

  • RAID 6: Reed-Solomon codes with Galois field arithmetic

  • Custom algorithms for recovering from beyond-rated failures

Virtual Reconstruction:

  • Hardware-independent array assembly

  • Real-time parameter testing and validation

  • Cross-platform file system support

Physical Recovery Integration:

  • Simultaneous multi-drive cleanroom operations

  • Component-level PCB repair with ROM preservation

  • Firmware-level access and modification

Why Choose Swansea Data Recovery?

  • 25 Years of Complex RAID Expertise: Specialized knowledge in parity-based array recovery

  • Mathematical Recovery Methods: Advanced algorithms for beyond-rated failures

  • Multi-Drive Cleanroom Capabilities: Simultaneous physical recovery of multiple failed drives

  • Proprietary System Knowledge: Expertise in vendor-specific implementations

  • Free Comprehensive Diagnostics: Detailed assessment and fixed-price quotation

Contact Swansea Data Recovery today for a free, confidential evaluation of your failed RAID 5, 6, or 10 array. Trust the UK’s leading complex storage recovery specialists for mission-critical data recovery.

Featured Article

Case Study: Critical Recovery from a DELL PowerEdge 2600 RAID 5 Array Following Controller Configuration Corruption

Client Profile: User of a DELL PowerEdge 2600 server with a 3-disk RAID 5 array.
Presenting Issue: Catastrophic array failure and server unbootability after attaching an external bootable drive. The RAID controller reports the array as offline or missing, with all data inaccessible.

The Fault Analysis

The client’s action of introducing an external bootable drive likely caused a conflict with the existing RAID controller’s configuration, stored in its NVRAM. The DELL PowerEdge 2600 typically uses a PERC (PowerEdge Expandable RAID Controller) series card. These controllers are highly sensitive to their boot order and configuration integrity.

Our diagnosis pointed to one of two specific failure scenarios:

  1. Configuration Metadata Corruption: The introduction of the new drive may have caused the controller to re-initialize its configuration, overwriting the critical metadata that defined the RAID 5 array’s parameters (disk order, stripe size, parity rotation algorithm, and start data offset). The array’s data remained intact on the physical drives, but the “map” to reassemble it was lost.

  2. Boot Priority Conflict and Partial Rebuild Initiation: If the controller mistakenly tried to boot from the new drive or treated it as a member of the array, it may have attempted an incorrect rebuild or consistency check, leading to the corruption of the parity data across the stripes. This would render the entire logical volume inaccessible.

The server’s failure to boot and the subsequent dropping of the data disks from the controller’s BIOS are clear indicators of a corrupted volatile configuration on the controller itself.

The Bracknell Data Recovery Solution

Recovering from this scenario required a forensically sound approach that completely bypassed the original, faulty RAID controller to manually reconstruct the array in software.

Phase 1: Physical Drive Stabilisation and Forensic Imaging
Each of the three hard drives from the array was carefully removed from the server and labelled according to their original bay positions.

  • Individual Drive Diagnostics: Each drive was connected to our PC-3000 system and DeepSpar Disk Imager for individual sector-level diagnostics. This step was critical to rule out concurrent physical media failure on any single drive, which would have compounded the logical corruption.

  • Sector-Level Imaging: We created full, bit-for-bit forensic images of all three drives onto our secure recovery storage. This process ensured all subsequent recovery work was performed on the images, preserving the original drives in their exact state. The imaging logs confirmed all three drives were physically healthy, confirming the issue was purely controller-configuration based.

Phase 2: RAID Parameter Analysis and Virtual Reconstruction
With the three disk images, the core task of reverse-engineering the original RAID parameters began.

  1. Stripe Size and Order Determination: Using our proprietary software, we performed a block analysis across all three images, searching for repetitive data patterns and parity blocks. By analysing the cyclic redundancy of data and parity across the drives, we empirically determined the stripe size (e.g., 64KB, 128KB) and the disk order (which physical drive was the first member of the array). An incorrect disk order would result in nonsensical data.

  2. Parity Rotation and Direction Identification: RAID 5 can use different parity rotation schemes (left-asymmetric, right-asymmetric, etc.). We tested these algorithms against the imaged data, looking for a configuration where the calculated parity (using a XOR operation across the corresponding blocks in the stripe) matched the stored parity on the designated drive. This confirmed the parity rotation algorithm and the data direction.

  3. File System Header Validation: Once a potential set of parameters was assembled, we built a virtual RAID 5 in our software. We then checked the start of this virtual volume for a valid NTFS Boot Sector (EB 52 90 4E 54 46 53). A valid boot sector confirmed we had correctly identified the start data offset and all other parameters.

Phase 3: Logical Volume Assembly and Data Extraction
After successfully defining the virtual RAID, our software seamlessly assembled the disk images into a single, coherent logical volume.

  • File System Traversal: We mounted the virtual volume and traversed the Master File Table (MFT) of the NTFS file system. The MFT was found to be entirely intact, as the physical drives had not suffered any data loss; only the controller’s “map” was lost.

  • Data Integrity Verification: We performed checksum verification on a sample of recovered files, confirming that the data and file structure were perfectly reconstructed. The client’s folder structure for each computer was fully restored.

Conclusion

The data loss was caused by a corruption of the RAID controller’s volatile configuration metadata, triggered by a hardware addition. The controller lost the instructions to properly assemble the RAID 5 set, rendering the perfectly healthy physical drives unreadable as a group. Our recovery success was contingent on completely bypassing the failed hardware controller, using forensic analysis to manually deduce its original configuration, and then reconstructing the array virtually in software.

The recovery was executed with 100% success, restoring the entire multi-folder directory structure and all client data from the failed array.

Bracknell Data Recovery – 25 Years of Technical Excellence
When your complex storage system like RAID fails due to controller error or configuration corruption, trust the UK’s No.1 HDD and SSD recovery specialists. We possess the specialised knowledge and tools to manually reconstruct and recover data from the most challenging multi-disk scenarios.

Client Testimonials

“ I had been using a Lacie hard drive for a number of years to backup all my work files, iTunes music collection and photographs of my children. One of my children accidently one day knocked over the hard drive while it was powered up. All I received was clicking noises. Swansea data recovery recovered all my data when PC World could not.  ”

Morris James Swansea

“ Apple Mac Air laptop would not boot up and I took it to Apple store in Grand Arcade, Cardiff. They said the SSD hard drive had stopped working and was beyond their expertise. The Apple store recommended Swansea data recovery so I sent them the SSD drive. The drive contained all my uni work so I was keen to get everything recovered. Swansea Data Recovery provided me a quick and professional service and I would have no hesitation in recommending them to any of my uni mates. ”

Mark Cuthbert Cardiff

“ We have a Q-Nap server which was a 16 disk raid 5 system. Three disks failed on us one weekend due to a power outrage. We contacted our local it service provider and they could not help and recommended Swansea Data Recovery. We removed all disks from server and sent them to yourselves. Data was fully recovered and system is now back up and running. 124 staff used the server so was critical for our business. Highly recommended. ”

Gareth Davies Newport Wales

“ I am a photographer and shoot portraits for a living. My main computer which I complete all my editing on would not recognise the HDD one day. I called HP support but they could not help me and said the HDD was the issue. I contacted Swansea Data Recovery and from the first point of contact they put my mind at ease and said they could get back 100% of my data. Swansea Data Recovery have been true to their word and recovered all data for me within 24 hours. ”

Iva Evans Cardiff

“ Thanks guys for recovering my valuable data, 1st rate service. ”

Don Davies Wrexham

“ I received all my data back today and just wanted to send you an email saying how grateful we both are for recovering our data for our failed iMac.  ”

Nicola Ball Cardiff

“ Swansea Data Recovery are a life saver 10 years at work was at the risk of disappearing forever until yourselves recovered all my data, 5 star service!!!!!  ”

Manny Baker Port Talbot Wales