RAID 1 Data Recovery

Staines Data Recovery: The UK’s No.1 RAID 1 Data Recovery Specialists

For 25 years, Staines Data Recovery has been the UK’s leading expert in recovering data from failed RAID 1 (mirror) arrays. While RAID 1 provides redundancy by maintaining identical copies of data on two or more drives, this simplicity can be deceptive. Complex failure scenarios involving simultaneous drive degradation, controller issues, and logical corruption require expert intervention. Our engineers possess deep expertise in reconciling divergent mirror copies and extracting a single, coherent dataset from seemingly hopeless situations.

Supported NAS Brands & Popular Models (for RAID 1 configurations)

Top 15 NAS/External RAID Brands & Popular Models:

1. Synology: DiskStation DS220+, DS720+, DS923+

2. QNAP: TS-233, TS-264, TS-453D

3. Western Digital (WD): My Cloud EX2 Ultra, My Book Duo

4. Seagate: IronWolf NAS, Expansion NAS

5. Netgear: ReadyNAS 212, RN3138

6. Buffalo Technology: LinkStation 520DN, TeraStation 3410DN

7. Drobo: 5C, 5N2

8. Dell EMC: PowerVault NX3240

9. Hewlett Packard Enterprise (HPE): ProLiant MicroServer Gen10 Plus

10. Asustor: AS5304T, AS6704T

11. Terramaster: F4-423, T9-450

12. LaCie: 2big RAID, 5big RAID

13. Lenovo: ThinkSystem SN500

14. Promise Technology: Pegasus32 R2, SmartSTOR MS12

15. Thecus: N2350, N4810

Top 15 RAID 1 Rack Server Brands & Popular Models:

1. Dell EMC: PowerEdge R750xs, PowerEdge R660xs

2. HPE: ProLiant DL360 Gen11, ProLiant DL320 Gen11

3. IBM/Lenovo: ThinkSystem SR630 V2, SR670 V2

4. Fujitsu: Primergy RX2530 M6

5. Cisco: UCS C240 M7

6. SuperMicro: SuperServer 2024US-TR4T+

7. Adaptec (by Microchip): Series 8e, SmartRAID 3162-16e

8. Areca: ARC-8050T3-16

9. HighPoint: RocketRAID 3744A

10. ATTO: FastStream NS 1700

11. Promise Technology: VTrak E610fD

12. Infortrend: EonStor DS 3024R

13. NetApp: FAS 2820

14. HPE: ProLiant DL180 Gen10

15. Dell EMC: PowerVault MD3460

30 Critical RAID 1 Errors & Our Technical Recovery Processes

RAID 1 recovery involves managing mirror synchronization, controller metadata, and individual drive health. Our process is methodical and designed to extract the most complete dataset possible.

1. Simultaneous Dual Drive Failure

• Problem: Both drives in a 2-drive mirror fail at approximately the same time, typically due to power surge, environmental factors, or identical wear patterns.

• Technical Recovery Process: Each drive undergoes independent physical recovery in our Class 100 cleanroom. This may involve head stack replacements, PCB repairs, or firmware corruption repair using PC-3000 systems. After both drives are successfully imaged, we perform a sector-by-sector comparison to identify which drive has the most recent and complete data set, creating a hybrid image from the best available sectors.

2. RAID Controller Failure with Configuration Loss

• Problem: The hardware RAID controller fails completely, losing the configuration that defines the mirror set. The individual drives are healthy but cannot be accessed as an array.

• Technical Recovery Process: We create sector-by-sector images of both drives. Since RAID 1 drives are exact copies, we can directly mount either image to access the data. To ensure data integrity, we perform a checksum comparison between the two images and use the drive with the fewer read errors as the primary data source.

3. Split-Brain Mirror Scenario

• Problem: After a controller failure or improper shutdown, each drive in the mirror is written to independently, creating two different datasets. The controller cannot determine which copy is valid.

• Technical Recovery Process: We image both drives and perform a binary comparison at the sector level. Using file system metadata timestamps (NTFS $MFT modify times, EXT4 journal timestamps), we identify which copy contains the most recent valid data. We can also merge the datasets, preserving the most recent version of each file from either mirror.

4. Failed Mirror Rebuild Process

• Problem: After replacing a failed drive, the rebuild process is interrupted or fails, potentially corrupting data on both the new drive and the surviving drive.

• Technical Recovery Process: We image all drives involved – the original surviving drive, the partially rebuilt drive, and the failed drive (if recoverable). We analyze the rebuild progress and reconstruct the pre-rebuild state using the original survivor’s image. Any data written during the failed rebuild is discarded to maintain consistency.

5. Bad Sectors on the Surviving Drive

• Problem: After one drive fails completely, the surviving drive develops bad sectors, making portions of the mirror unreadable.

• Technical Recovery Process: The surviving drive is connected to a DeepSpar Disk Imager or PC-3000 with read retry control. We use aggressive read techniques including thermal management and head parameter adjustments to recover data from weak sectors. Any unrecoverable sectors represent permanent data loss unless the failed drive can be partially recovered.

6. Accidental Mirror Break and Reformat

• Problem: A user breaks the mirror relationship and reformats one drive, believing the data is safely mirrored elsewhere, when in fact both drives were affected.

• Technical Recovery Process: We image both drives. The reformatted drive may have overwritten the beginning sectors (partition table, file system metadata), but user data areas may remain intact. We attempt to reconstruct the file system from the unaffected drive or perform raw file carving on both drives to recover maximum data.

7. Firmware Corruption on One Mirror Drive

• Problem: One drive suffers firmware corruption in the service area, making it unrecognizable to the system, while the other drive remains healthy.

• Technical Recovery Process: Using PC-3000 tools, we access the corrupted drive’s firmware area directly via terminal commands. We repair or regenerate critical modules such as the translator, SMART data, and adaptive parameters. Once the drive is functional, we image it completely and verify against the healthy mirror.

8. Power Surge Damaging One Drive’s PCB

• Problem: A power surge damages the PCB of one drive in the mirror, while the other drive remains unaffected.

• Technical Recovery Process: We diagnose the damaged PCB, typically finding shorted TVS diodes near the power input. After diode removal/replacement, if the controller IC is damaged, we perform a PCB swap with ROM transfer – moving the unique adaptive data chip to an identical donor PCB. The recovered drive is then imaged and compared to its mirror.

9. File System Corruption on the Array

• Problem: The file system on the mirrored volume becomes corrupted due to software error, virus, or unsafe shutdown, affecting both drives identically.

• Technical Recovery Process: We image one drive (choosing the one with better health metrics) and work on the image. Using advanced file system repair tools, we rebuild corrupted metadata structures. For NTFS, we may use the $MFTMirr file; for EXT4, we use backup superblocks. Having two identical copies allows us to verify repairs against the second drive.

10. Multiple Drive Degradation in Expanded RAID 1+0

• Problem: In a multi-drive RAID 10 array, multiple drives fail within the same mirror sets, compromising the striped array’s integrity.

• Technical Recovery Process: We recover each failed drive individually. The recovery process involves first rebuilding each damaged mirror set using the best available drive from each pair, then reconstructing the stripe across the recovered mirrors. This requires precise synchronization of recovery efforts across multiple drives.

11. Controller Cache Corruption During Write Operations

• Problem: The controller’s cache becomes corrupted during write operations, causing inconsistent data to be written to the mirrors.

• Technical Recovery Process: We examine both drives for write inconsistencies at the sector level. Using file system journaling information (NTFS $LogFile, EXT4 journal), we determine the last consistent transaction point and roll back both drives to this state using specialized software tools.

12. Drive Size Mismatch After Replacement Attempt

• Problem: A failed drive is replaced with a smaller capacity drive, preventing the mirror from being rebuilt.

• Technical Recovery Process: We recover the original failed drive through physical means. If unsuccessful, we work with the surviving drive only. The capacity mismatch issue is bypassed by imaging the surviving drive and creating a virtual copy that can be mounted independently.

13. S.M.A.R.T. Errors Causing Drive Rejection

• Problem: One drive develops S.M.A.R.T. errors that cause the controller to mark it as failed, even though it may still be readable.

• Technical Recovery Process: We use professional tools to bypass S.M.A.R.T. monitoring and force read access to the marginal drive. The drive is imaged as quickly as possible before complete failure, and the data is reconciled with the healthy mirror.

14. NAS-Specific RAID 1 Implementation Corruption

• Problem: The proprietary RAID implementation on systems from Synology, QNAP, or Drobo becomes corrupted.

• Technical Recovery Process: We remove the drives and analyze the proprietary metadata structures. For Linux-based systems (Synology/QNAP), we often find standard MD-RAID signatures that can be reconstructed. For proprietary systems like Drobo, we use specialized tools to decode the metadata and reassemble the volume.

15. Physical Damage to One Drive (Impact/Water)

• Problem: One drive suffers physical damage from impact or liquid exposure, while its mirror remains physically undamaged but may be logically corrupted.

• Technical Recovery Process: The damaged drive undergoes full physical recovery including cleanroom work, while the undamaged drive is logically imaged. The two datasets are compared to fill any gaps in the physically recovered drive’s image.

16. Incorrect Drive Reassembly Order

• Problem: After maintenance, drives are reinstalled in the wrong order, confusing the controller about mirror relationships.

• Technical Recovery Process: We test various drive order configurations virtually using drive images. The correct order is identified when the controller accepts the configuration and presents valid data. This process is done on imaged copies to prevent further damage.

17. Partial Controller Failure Causing Desynchronization

• Problem: A failing controller intermittently writes to only one drive, causing the mirrors to become increasingly out of sync.

• Technical Recovery Process: We image both drives and perform a binary comparison to identify diverged sectors. Using file system metadata, we determine which version of each diverged sector is correct, typically choosing the one with valid structural metadata.

18. Encryption Key Loss on Self-Encrypting Drives

• Problem: The mirror consists of self-encrypting drives (SEDs) and the encryption key is lost or corrupted.

• Technical Recovery Process: We attempt to recover the key from the drive’s firmware area using PC-3000 tools. If unsuccessful, we may need to perform a chip-off recovery on both drives and attempt to break the encryption, which is often computationally infeasible with modern encryption.

19. Virus Infection on the Mirror Set

• Problem: Ransomware or other malware encrypts or corrupts the data on the mirrored volume.

• Technical Recovery Process: We image both drives. If the infection occurred at different times, we may find unencrypted versions of files on the drive that was offline during part of the attack. We also check for shadow copies or backup versions that might predate the infection.

20. Failed Operating System Update on the Array

• Problem: An OS update fails mid-process, corrupting system files on both mirrors.

• Technical Recovery Process: We mount the drive images as read-only and use file system tools to roll back to pre-update states using transaction logs or volume shadow copies. The mirroring ensures we have two chances to find a consistent pre-update state.

21. Backplane Failure Simulating Drive Failure

• Problem: A server backplane failure makes one or both drives appear failed when they are actually functional.

• Technical Recovery Process: We remove the drives and connect them directly to our recovery hardware. If the drives are healthy, we image them and provide the customer with usable data while they repair the server hardware.

22. Drive Firmware Bug Causing Read/Write Errors

• Problem: A specific firmware version on the drives causes compatibility issues with the RAID controller.

• Technical Recovery Process: We update or downgrade the drive firmware to a stable version in an isolated environment, then image the drives. In some cases, we may need to work with the manufacturer to obtain special firmware versions.

23. Multiple Bad Sectors Across Both Drives

• Problem: Both drives develop bad sectors in different locations, creating a situation where no single drive has a complete dataset.

• Technical Recovery Process: We perform advanced imaging on both drives with sector skipping and retry algorithms. The resulting images are combined at the sector level, using each drive to fill in the other’s bad sectors. This creates a complete hybrid image.

24. Accidental Deletion of Files from Active Mirror

• Problem: Files are accidentally deleted from the active mirror and the deletion propagates to the other mirror.

• Technical Recovery Process: We image both drives and perform file system analysis to recover deleted file entries. With two copies, we can often recover more complete metadata and have a better chance of file reconstruction.

25. Controller Battery Failure Causing Cache Loss

• Problem: The controller’s backup battery fails, resulting in loss of cached data during a power outage.

• Technical Recovery Process: We examine both drives for inconsistent write patterns and use file system repair tools to bring the volume to a consistent state, potentially losing recently written data but preserving structural integrity.

26. Drive Temperature Differential Causing Performance Issues

• Problem: Significant temperature differences between drives in the same array cause timing issues and write errors.

• Technical Recovery Process: We image both drives in a controlled temperature environment and verify data consistency. The recovery process includes thermal management to ensure stable operation during imaging.

27. SAS vs SATA Compatibility Issues

• Problem: Mixing SAS and SATA drives in a mirror configuration causes controller compatibility problems.

• Technical Recovery Process: We image each drive using appropriate interfaces (SAS for SAS drives, SATA for SATA drives) and combine the images virtually, accounting for any sector size differences (520 vs 512 bytes).

28. Expired SSL Certificate on Management Interface

• Problem: The RAID controller’s web management interface becomes inaccessible due to an expired SSL certificate, preventing configuration changes.

• Technical Recovery Process: We access the controller via direct serial connection or KVM to bypass the web interface, or we remove the drives and access them directly via our recovery hardware.

29. Drive Security Erase Command Execution

• Problem: A security erase command is executed on one drive, wiping its content while the mirror may still contain data.

• Technical Recovery Process: We immediately image the non-erased drive to preserve data. For the erased drive, we may attempt data recovery from service areas or perform microscopic analysis for residual magnetic data, though success is unlikely with modern sanitize commands.

30. Complex Multi-Terabyte Mirror with Mixed Issues

• Problem: A large, multi-terabyte RAID 1 array exhibits multiple simultaneous issues including physical damage, logical corruption, and controller problems.

• Technical Recovery Process: This requires a coordinated multi-stage approach: physical recovery of damaged drives, logical repair of file systems, and virtual reconstruction of the array relationship. Each stage is documented and verified before proceeding to the next, with continuous data validation throughout the process.

Why Choose Staines Data Recovery for Your RAID 1?

• 25 Years of RAID 1 Expertise: We have handled every possible mirror failure scenario.

• Mirror Synchronization Mastery: Experts in reconciling split-brain and out-of-sync scenarios.

• Complete Recovery Suite: From cleanroom physical recovery to advanced logical repair.

• Vendor-Specific Knowledge: Deep understanding of different controller implementations.

• Free Diagnostics: Comprehensive analysis and clear, fixed-price quotation.

• “No Data, No Fee” Guarantee: You only pay for successful recovery.

Contact Staines Data Recovery today for your free, expert RAID 1 diagnostic. Trust the UK’s leading mirror recovery specialists to retrieve your critical data.