Raid 1 Recovery

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

For 25 years, Swansea Data Recovery has been the UK’s leading specialist in recovering data from failed RAID 1 (mirrored) arrays. While RAID 1 offers redundancy by duplicating data across two or more drives, it is not immune to complex failures that can render data inaccessible. We provide professional recovery services for all types of RAID 1 systems, from simple 2-disk mirrors to complex multi-drive mirrored sets, across hardware controllers, software implementations, and NAS devices. Our state-of-the-art laboratory combines advanced logical recovery techniques with certified cleanroom facilities to handle the unique challenges of mirrored array failures.

Supported RAID 1 Systems & NAS Devices

Top 15 NAS Brands & Popular Models Supporting RAID 1 in the UK:

  1. Synology: DiskStation DS220+, DS720+, DS920+

  2. QNAP: TS-253D, TS-431X, TVS-872X

  3. Western Digital (WD): My Cloud EX2 Ultra, My Cloud Pro PR2100

  4. Seagate: IronWolf 2-Bay NAS, BlackArmor NAS 110

  5. Buffalo Technology: LinkStation LS210D, TeraStation 1200D

  6. Netgear: ReadyNAS RN212, RN214

  7. Drobo: 5C, 5N2

  8. Asustor: AS3202T, AS5304T

  9. Thecus: N2350, N4810

  10. Terramaster: F2-422, D5-300

  11. LaCie: 2big, 5big

  12. Lenovo: IX2-DL, PX4-300D

  13. D-Link: DNS-320L, DNS-327L

  14. ZyXEL: NAS326, NAS520

  15. Mediasonic: HFR2-SU3S2

Top 15 RAID 1 Server Brands & Popular Models:

  1. Dell EMC: PowerEdge R740xd, R750, PowerVault MD1400

  2. Hewlett Packard Enterprise (HPE): ProLiant DL380 Gen10, ML350 Gen10

  3. IBM/Lenovo: ThinkSystem SR650, ST250

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

  5. Fujitsu: PRIMERGY RX2530 M5, TX1330 M3

  6. Cisco: UCS C240 M5

  7. Oracle: Sun Fire X4270 M3

  8. Intel: Server System S2600WF

  9. Acer: Altos T350 F2

  10. ASUS: RS500A-E9-RS12

  11. Promise Technology: VTrak E610sD

  12. Infortrend: EonStor DS 1024D

  13. Areca: ARC-8050T3

  14. Adaptec by Microchip: Adaptec 81685ZQ

  15. QNAP: TS-EC2480U R2

Top 25 RAID 1 Errors & Our Technical Recovery Process

RAID 1 recovery requires sophisticated analysis of mirror consistency, controller metadata, and drive synchronization. Here is a detailed breakdown of our specialised processes.

1. Simultaneous Mirror Drive Failure

  • Summary: Both drives in a 2-drive RAID 1 array fail mechanically or electronically at the same time, completely defeating the redundancy.

  • Technical Recovery: Each drive undergoes independent physical recovery in our Class 100 cleanroom. This may involve separate head stack assembly transplants from compatible donors, PCB repairs with ROM transfers, or spindle motor replacements. We then create sector-by-sector images of both drives using hardware imagers (PC-3000) with adaptive reading. The recovery focuses on creating a complete dataset by combining readable sectors from both drives, effectively using each drive to fill in gaps from the other.

2. Split Brain/Mirror Desynchronization

  • Summary: The two mirror drives contain different data because the controller lost track of which drive was current, or writes were not properly synchronized.

  • Technical Recovery: We image both drives and perform a sector-by-sector binary comparison using tools like WinHex or custom scripts. We analyse the file system journals ($LogFile for NTFS, journal for EXT4) on both drives to determine which contains the most recent valid transactions. The drive with the most recent consistent journal entries is typically designated as the primary source, while the other drive provides fallback for corrupted sectors.

3. Controller Failure with Metadata Corruption

  • Summary: The RAID controller fails and loses its configuration metadata, including which drive is primary and the mirror synchronization status.

  • Technical Recovery: We create forensic images of both drives and analyse them independently. Using file system forensic tools, we determine which drive has the most recent write activity by examining metadata timestamps (MFT for NTFS, inode timestamps for EXT4). We then manually reconstruct the controller configuration or simply access the most current drive directly, bypassing the failed controller entirely.

4. Failed Rebuild onto Failed Drive

  • Summary: A user replaces a failed drive, but the controller incorrectly identifies the healthy drive as failed and begins rebuilding old/outdated data from the failed drive onto the good drive.

  • Technical Recovery: This is a critical scenario requiring immediate power-down. We image all drives involved. We then perform binary analysis to identify which sectors were overwritten during the failed rebuild. By comparing pre-rebuild and post-rebuild states (using file system metadata timestamps), we can reconstruct the original data from the good drive while recovering any unique data that hadn’t been overwritten from the partially rebuilt drive.

5. Accidental Mirror Break and Data Write

  • Summary: A user breaks the mirror relationship and writes different data to both drives, then attempts to reestablish the mirror.

  • Technical Recovery: We image both drives and treat them as separate entities. Using file system analysis, we determine the timeline of writes to each drive. We typically recover data from the drive with the most valuable content, or we merge data from both drives by prioritizing files based on their last modification timestamps, effectively treating it as two separate recovery jobs.

6. Bad Sectors on Both Mirror Drives

  • Summary: Both drives develop bad sectors in different locations, creating a situation where no single drive has a complete copy of all data.

  • Technical Recovery: We use hardware imagers with advanced read retry capabilities on both drives. The imagers perform multiple read attempts with adjusted timeout parameters and may apply firmware-level tweaks to temporarily reduce read retry thresholds. We then create a consolidated image by using sectors from Drive A where readable, and filling in missing sectors from the same locations on Drive B, creating a complete “virtual” drive composed of the best sectors from both mirrors.

7. Partial Controller Failure with Incomplete Writes

  • Summary: The controller begins failing intermittently, writing data to one drive but not its mirror, creating synchronization gaps.

  • Technical Recovery: We image both drives and perform a sophisticated comparison that identifies write patterns and gaps. By analysing the file system journal and metadata timestamps, we can identify which drive has the most consistent write history and use it as the primary source. The secondary drive provides data for sectors that were corrupted during the controller’s failure episodes.

8. Drive Removal and Reinsertion in Wrong Order

  • Summary: Drives are removed for maintenance and reinserted in incorrect bays, causing the controller to misidentify the mirror relationship.

  • Technical Recovery: We image both drives and analyse them as independent entities. Since RAID 1 mirrors are typically identical at the data level (unlike RAID 0), the physical bay order is less critical. We focus on identifying which drive has the most current data through file system analysis and use that as our primary recovery source, regardless of physical position.

9. Firmware Corruption on Primary Drive

  • Summary: The drive identified as primary by the controller suffers firmware corruption, making it unreadable through normal means.

  • Technical Recovery: We use specialized tools (PC-3000) to place the affected drive into technological mode, bypassing the corrupted public firmware. We can then directly access the service area to repair damaged modules or read the user data area directly. Meanwhile, the secondary drive serves as a verification source and backup if any sectors prove unrecoverable from the primary.

10. Virus/Ransomware Encryption on Live Array

  • Summary: Malware encrypts files on the active RAID 1 volume, with changes mirrored to both drives in real-time.

  • Technical Recovery: We image both drives and search for residual unencrypted data in slack space, shadow copies, or temporary files. For ransomware, we check both drives for local backup copies or version history that might have escaped encryption. The mirroring means we typically can’t find an unencrypted copy, but having two identical encrypted copies allows verification during decryption attempts.

11. Power Surge Damaging Multiple Components

  • Summary: A power surge damages components on both drive PCBs and potentially the RAID controller.

  • Technical Recovery: We diagnose and repair all damaged PCBs, typically replacing TVS diodes, fuses, and motor driver ICs. Critical to this process is transferring the unique adaptive data from each original PCB ROM to its replacement board. We then image all drives and proceed with analysis, bypassing the potentially damaged controller.

12. Reinitialization with Partial Overwrite

  • Summary: The array is accidentally reinitialized, overwriting the beginning of both drives but leaving later sectors intact.

  • Technical Recovery: We image both drives and search for backup file system structures. For NTFS, we look for backup boot sectors typically located at the volume’s end. We also perform raw carving across both drives, using the duplicate copies to verify recovered files. The mirroring provides a validation mechanism – files found identically on both drives are almost certainly intact.

13. S.M.A.R.T. Errors Causing False Failure Flags

  • Summary: One drive develops non-critical S.M.A.R.T. errors that cause the controller to incorrectly mark it as failed.

  • Technical Recovery: We assess the actual severity of the S.M.A.R.T. errors through detailed analysis. Many predictive errors don’t immediately affect data readability. We use hardware imagers to create stable images of both drives, often by temporarily disabling certain S.M.A.R.T.-related features. We then use the “failed” drive as a primary source if it proves readable, with the other drive as verification.

14. Backplane Connection Corruption

  • Summary: Faulty backplane connections cause read/write errors that the controller interprets as drive failures.

  • Technical Recovery: We remove both drives from the problematic enclosure and connect them directly to controlled ports on our forensic workstations. This eliminates backplane issues and allows us to obtain stable images of each drive. We then analyse both drives to determine their actual health status and recover data from the most intact copy.

15. File System Corruption with Mirroring of Corruption

  • Summary: File system corruption occurs and is faithfully mirrored to both drives.

  • Technical Recovery: We image both drives and focus on file system repair techniques. For NTFS, we repair the Master File Table ($MFT) using its mirror copy ($MFTMirr). For HFS+, we rebuild the Catalog File using allocation file data. Having two identical copies allows us to verify repairs and ensure we’re working with consistent data structures across both drives.

16. Manufacturing Defects in Mirror Drives

  • Summary: Drives from the same manufacturing batch suffer from identical defects that manifest in both mirrors.

  • Technical Recovery: We address each drive individually but apply lessons learned from the first drive to the second. The identical nature of the defects means we can develop a specific read strategy or firmware patch that works for both drives, improving recovery efficiency.

17. Incorrect Drive Replacement Procedure

  • Summary: A user replaces a failed drive but uses an incompatible model or incorrect procedure, causing array synchronization failure.

  • Technical Recovery: We obtain a compatible donor drive that matches the original specifications. We then work with the original healthy drive to create a new mirror set in our controlled environment, or simply image the healthy drive directly to preserve the data without attempting a risky resync.

18. Thermal Damage to Multiple Drives

  • Summary: Poor ventilation causes overheating damage to both drives in the array.

  • Technical Recovery: Each drive requires individual assessment and stabilization. This may include PCB rework to address heat-damaged components and cleanroom work for media issues. We image each drive after stabilization, with our hardware imagers configured to handle the increased read instability typical of heat-damaged media.

19. Controller Battery Failure with Cache Data Loss

  • Summary: The controller’s battery backup unit fails, resulting in loss of cached writes that hadn’t been committed to both drives.

  • Technical Recovery: We image both drives and compare them to identify synchronization gaps. Using file system journal analysis, we can identify incomplete transactions and either complete them logically or roll them back to maintain file system consistency. The drive with the most recent committed writes typically serves as our primary source.

20. Multiple Point-in-Time Mirror States

  • Summary: A complex failure leaves each drive with data from different time points due to interrupted resynchronization.

  • Technical Recovery: We image all drives and perform detailed timeline analysis using file system metadata. By examining modification timestamps, journal entries, and file system transaction records, we reconstruct the most recent consistent state across all available drives, creating a coherent virtual volume from temporally disparate sources.

21. NAS Operating System Corruption with RAID 1

  • Summary: The NAS device’s operating system becomes corrupted, preventing access to the RAID 1 volume.

  • Technical Recovery: We remove both drives from the NAS and connect them directly to our recovery workstations. We then analyse each drive independently to determine which has the most current data, completely bypassing the corrupted NAS operating system. The drive with the most recent file system activity becomes our primary recovery source.

22. Sector Size Mismatch After Replacement

  • Summary: A failed drive is replaced with one of different sector size (512e vs 4Kn), preventing proper mirror synchronization.

  • Technical Recovery: We obtain a drive matching the original sector size specifications. If the original failed drive is unrecoverable, we work with the remaining healthy drive. Our analysis focuses on the healthy drive’s data, with the replacement drive serving only as a potential source for any unique data that might have been written during the brief period it was active.

23. Human Error During Array Management

  • Summary: Incorrect commands are issued to the array during management, causing unintended mirror breaks or data loss.

  • Technical Recovery: We assess the logical state of both drives through comprehensive imaging. Depending on the specific error, we may need to reconstruct broken mirror metadata, repair file systems damaged by incorrect operations, or extract data from shadow copies or backup metadata that survived the management error.

24. Complex Multi-Drive Mirror Set Failure

  • Summary: In systems with more than two mirrored drives, multiple drives fail or desynchronize.

  • Technical Recovery: Each drive undergoes individual assessment and imaging. We then perform comparative analysis across all available drives to identify the most current and consistent data set. For n-way mirrors, we can tolerate n-1 failures and still recover complete data, making this one of the most robust scenarios for recovery despite its complexity.

25. Silent Data Corruption with Mirroring of Errors

  • Summary: Data corruption occurs at the application or file system level and is mirrored to both drives before detection.

  • Technical Recovery: We image both drives and search for backup copies of corrupted files in shadow copies, temporary directories, or backup metadata. For database applications, we examine transaction logs to identify and reverse corrupt transactions. The mirroring means we typically can’t find an uncorrupted version on the main data area, but having two identical copies allows checksum verification during repair attempts.

Why Choose Swansea Data Recovery for Your RAID 1?

  • 25 Years of Mirror Recovery Expertise: Specialized knowledge in handling mirrored array failures and synchronization issues

  • Advanced Comparative Analysis: Sophisticated tools for comparing and reconciling multiple mirror copies

  • Combined Physical & Logical Recovery: Full cleanroom capabilities alongside advanced logical reconstruction

  • Controller-Independent Recovery: Ability to bypass failed controllers and work directly with drive data

  • Free Diagnostics: Comprehensive assessment and clear, fixed-price quote before any work begins

Contact Swansea Data Recovery today for a free, confidential evaluation of your failed RAID 1 array. Trust the UK’s No.1 RAID 1 recovery specialists to recover your mirrored data with maximum integrity and minimal downtime.

Featured Article

Raid 1 Repair

QNAP TURBO 859 RAID 1:

I have been using a NTFS system to make a false RAID 1 on my QNAP Turbo server. The RAID 1 I created was mirroring several different drives across a single partition, and I had been working this way for several months. A lot of data was recorded on these drives, but I have suddenly discovered that one of the drives has failed. I have attempted a rebuild by inserting a new drive into the Turbo and removing the failed one, but I could not get the system to rebuild. The process started, but suggested that it would take 60 hours to complete. I waited for a few hours, and looked at how the rebuild was going. The new drive was reporting itself as RAW, and when I tried to view the partition using a Test program, I was not able to extract files. I did a recovery, and found a few files that are now on a USB drive. A lot more are missing. I have not been able to recover error logs to show when the fail occurred, and so I don’t know how much data I have lost from the array.

WD DRIVES RAID 1:

I have a pair of WD drives which each contain 1TB of storage. I had originally had them installed in a three-partition system, and one was the reserved disk for the OS, and the others were also running different systems for the computer. I realised that I was not doing a proper backup for my data, so created a mirror in the drives to hold and store my information. I removed one of the drives, and then replaced it, so that the array was supposed to be settling back into place to build the new array. However, when I plugged in the second drive, I instead got a warning that the disks were out of position, and the array is now not responding at all. I can’t replace the second drive into the system without getting this warning. I have data on the first OS drive which is needed to run the computer and some of the other programs on that OS, and without it I have no PC at all.

Raid 1 Repair

With a Raid 1 configuration in operation every time you write information to one drive the exact same information is then mirrored to another drive, as though you were copying it directly there without physically doing it yourself.

This setup, without mirroring or parity, is a good way of producing a second backup if you will without having to go to the trouble of producing it to a set timescale.

Another good aspect to this process is that should you update information on one copy it will automatically be updated to the other; rather like having a spare user to help you out.

But although this all sounds well and good there are problems that can be encountered when using the Raid 1 configuration and it is again important to have a brief understanding of the sorts of errors than can occur whilst running such a setup.

One of the most common problems facing this kind of setup – and it is a problem that faces many hard drives – is degradation. With constant use and the constant writing and rewriting of information back and forth the disks can eventually wear down or become sluggish.

With this in mind if you receive a critical error warning on your Raid 1 configuration it is best to shut the system down and call for professional assistance.

If there has been degradation caused to either one of the disks then any information you try and commit to them may either be corrupt or may not be saved at all. In this instance the whole idea of continuing to use the array is pointless, as you will have only a limited amount of information to fall back on if it can be recovered.

If you have received a critical error on your Raid 1 configuration it is best to contact us here at www.swanseadatarecovery.co.uk.

We have over a decade’s experience in working with Raid configurations and arrays and are on hand to help you make the transition back to a working system in as short a time as possible with the most information retrieved.

We may also be able to point you in the right direction when it comes to operating a more secure and reliable Raid configuration should it prove necessary.

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.   ”

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“ 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. ”

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“ 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. ”

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“ 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.   ”

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“ 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