Case Study: Recovery from a Compaq ProLiant RAID 5 Array Following a Partial and Corrupt Rebuild of Virtualized Servers

Client Profile: Business using a Compaq ProLiant server with a 7-disk RAID 5 array, running Small Business Server with multiple virtual machines. Presenting Issue: Following a single disk failure and subsequent replacement, the RAID controller reported a successful 100% rebuild. However, the server failed to boot. HP Business Support upgraded firmware and ran diagnostics but could not resolve the issue, which was later identified as a partial rebuild that only completed 42%.

The Fault Analysis

This scenario represents a catastrophic logical corruption within a complex storage hierarchy. The failure occurred at multiple levels:

1. Physical Media Failure: The original member disk suffered an electromechanical failure, likely a spindle motor seizure or bearing failure, causing the drive to drop from the array.

2. RAID Controller Logic Error: The core of the failure was a critical bug in the RAID controller's firmware. The controller incorrectly reported a 100% successful rebuild when, in fact, the process halted at 42%. This created a false positive success state, masking the underlying corruption. The partial rebuild wrote inconsistent data across the new disk, creating a split-brained array where some stripes had updated parity and data, while others remained in the degraded state.

3. File System Corruption: The Windows Small Business Server, installed on a Virtual Hard Disk (VHD/VHDX) or similar virtual disk file, has a multi-layered structure. The partial rebuild corrupted the NTFS file system within the virtual disk, specifically damaging critical metadata like the Master File Table ($MFT) and the NTFS $LogFile.

4. Virtualization Layer Corruption: The virtual disk files themselves are complex containers. A partial rebuild can corrupt the virtual disk header, parent disk links (in differencing chains), or the block allocation table (BAT) within the VHDX file, rendering the entire virtual machine inaccessible.

The Professional Data Recovery Laboratory Process

Recovery required a multi-stage forensic approach to first stabilize the physical media, then manually reconstruct the RAID, and finally decode the virtualized layers.

Phase 1: Physical Drive Stabilization and Forensic Imaging

We received 8 disks: the 7 original array members and the 1 new disk used in the failed rebuild.

1. Individual Drive Diagnostics: All 8 drives were connected to our PC-3000 system and DeepSpar Disk Imager for individual sector-level diagnostics and health assessment.

2. Motor Transplant on Failed Drive: The original failed drive was confirmed to have a spindle motor failure. In our Class 100 ISO 5 cleanroom, we performed a platter transplant, moving the entire stack of platters and the head stack assembly into an identical donor drive with a functional motor and PCB. This is a critical step to ensure all original data is accessible for the reconstruction.

3. Sector-Level Imaging: A full, sector-by-sector clone of all 8 drives was created onto our secure storage array. The imaging process for all drives was configured with read retry algorithms to handle any marginally unstable sectors, ensuring the most complete dataset for the subsequent logical reconstruction.

Phase 2: RAID Parameter Analysis and Virtual Reconstruction

With 8 forensic images, the task was to determine the correct state of the array.

1. Empirical Parameter Calculation: The RAID metadata on the controller was unreliable. Our software performed a block analysis across all 7 original disk images to empirically determine the RAID 5 parameters: stripe size (e.g., 64KB, 128KB), disk order, parity rotation algorithm (left-symmetric, right-symmetric), and data start offset.

2. Identifying the Rebuild Corruption: We then introduced the image of the new disk used in the partial rebuild. By performing a binary comparative analysis at the stripe level, we identified the exact LBA range (0% to 42%) where the rebuild had written new data and parity. This 42% portion was now a dangerous mix of old and new data.

3. Building a Coherent Virtual Array: We created two virtual RAID assemblies in our software:

   • Pre-Failure Array: Using only the 7 original disk images (including the now-recovered original failed drive), we built a virtual RAID 5 representing the array in its last known consistent state, prior to the rebuild.

   • Post-Rebuild Array Analysis: We analysed the corrupted 42% rebuilt section to determine which stripes, if any, contained valid data that was more recent than the pre-failure state.

Phase 3: Virtual Machine Container Reconstruction and Data Extraction

This was the most complex phase, dealing with the layered data structures.

1. Virtual Disk File Carving: From the coherent virtual RAID image, we located the large virtual disk files (e.g., .vhd, .vhdx, .vmdk). These files were likely fragmented across the array.

2. Virtual Disk Metadata Repair: Using specialized virtual disk parsing tools, we repaired the corrupted VHDX header and Block Allocation Table (BAT). The BAT, which maps sector offsets within the VHDX file to sectors on the host, was critically damaged by the partial rebuild. We manually rebuilt it by analysing the internal file system structures of the guest OS.

3. Guest File System Recovery: Once the virtual disk containers were logically repaired, we mounted them and processed the internal file systems (NTFS for Windows Server). We repaired the $MFT using its mirror ($MFTMirr) and replayed the NTFS $LogFile to achieve a transactionally consistent state.

4. Application-Level Consistency Check: For the recovered virtual servers, we verified the integrity of critical application data, such as the Active Directory database (NTDS.dit) and Exchange Server database (.edb), to ensure they were recoverable and consistent.

Conclusion

The client's server failure was a multi-layered disaster: a physical drive failure was compounded by a critical RAID controller firmware bug that falsely reported a successful rebuild, which in turn corrupted both the physical RAID stripes and the logical virtual disk structures. A professional lab's success in this scenario hinges on the ability to perform physical drive recovery, forensically reconstruct the RAID array by ignoring the controller's faulty metadata, and then meticulously repair the complex, layered data structures of virtualized environments. This process effectively "de-virtualizes" the recovery to access the core file systems.

The recovery was a success. By using the original 7 drives to reconstruct the pre-failure array state, we achieved a 98% recovery rate for both virtual servers, including all critical business data, user accounts, and company emails.

Swansea Data Recovery – 25 Years of Technical Excellence When your enterprise RAID system suffers a complex failure involving partial rebuilds and virtualized environments, trust the UK's No.1 HDD and SSD recovery specialists. Our expertise extends from cleanroom physical repairs to the forensic reconstruction of complex storage virtualizations, ensuring business continuity after catastrophic data loss. Contact us for a free diagnostic.

Case Study: Comprehensive Recovery from an Iomega GDHDU 2TB External Drive with Compound PCB and Firmware Corruption

Client Profile: User of an Iomega GDHDU 2TB external hard drive connected to a Dell Inspiron laptop running Windows 11. Presenting Issue: The drive failed without warning. While the USB bridge board received power (indicated by LED activity), the drive was not enumerated by the Windows operating system and failed to appear in Device Manager. The fault was replicated across multiple computers, confirming the issue was localized to the drive assembly itself.

The Fault Analysis

The client's symptoms pointed to a critical failure at the interface between the external enclosure's USB bridge and the native SATA hard drive inside. The fact that the USB bridge received power but the drive was not detected indicated one of two scenarios:

1. The USB-to-SATA bridge board was functional, but the internal hard drive was not responding to its commands.

2. The internal hard drive was failing to initialise, preventing the bridge board from presenting a valid USB Mass Storage Class device to the host computer.

Our internal diagnostics confirmed a compound failure of the hard drive's internal components.

The Professional Data Recovery Laboratory Process

Phase 1: Physical Deconstruction and Component-Level Diagnosis

1. Drive Extraction & Visual Inspection: The 2TB 3.5" SATA hard drive was carefully removed from the Iomega GDHDU enclosure. A macroscopic and then microscopic inspection of the Printed Circuit Board (PCB) was performed.

2. Electronic Forensics: The PCB was subjected to a detailed electronic diagnostic:

   • Power Rail Testing: Using a multimeter, we detected a short circuit on the +5V rail, traced to a failed Transient Voltage Suppression (TVS) diode (D2). This diode is designed to sacrifice itself during a voltage spike to protect the more sensitive main controller and motor driver ICs.

   • Firmware Chip Interrogation: The drive's unique adaptive data and firmware are stored on a serial EEPROM chip, typically a 25-series NOR flash (e.g., Winbond 25X40AV). This chip was unresponsive to a SPI (Serial Peripheral Interface) read attempt via a dedicated programmer, indicating potential corruption of its contents or physical damage to the chip itself. This constituted the factory firmware damage.

   • Motor Driver IC Assessment: The SMOOTH or L7250-series motor driver IC was tested for shorts between its power input pins and ground. A short here would indicate a catastrophic failure requiring a full PCB replacement.

Phase 2: PCB Repair and Firmware Reconstruction

This phase involved restoring the electronic and logical functionality of the drive.

1. Component-Level Repair: The shorted TVS diode was carefully desoldered from the PCB. This single action often restores electrical continuity. The board was re-tested, confirming the short was cleared and the +5V rail was now stable.

2. Donor PCB Sourcing and NV-RAM Transplantation: Due to the firmware chip corruption, a simple board swap was insufficient. We sourced an identical donor PCB from our inventory, matching the model number, PCB revision, and firmware version.

   • The corrupted NV-RAM serial EEPROM chip was desoldered from the patient's original PCB.

   • Using a SPI NAND/NOR Flash Programmer (such as the RT809H), we attempted to read the contents of the original chip. The read process failed, confirming physical corruption of the non-volatile memory.

   • We then programmed a blank EEPROM chip with a virgin firmware module from our extensive technical database, specific to the drive's model and family. This module contained the essential adaptive parameters to allow the drive to initialise.

3. Firmware Adaptation: This new chip was soldered onto the donor PCB. The repaired assembly was then installed on the patient drive.

Phase 3: Firmware-Level Initialisation and Sector Imaging

With a functional PCB, we could now communicate with the drive at a deep level.

1. Terminal Access: The drive was connected to our PC-3000 system with Data Extractor. We established a terminal connection and issued an IDN (Identify Device) command. The drive responded correctly, confirming successful initialisation.

2. Service Area (SA) Verification: We proceeded to read critical modules from the drive's System Area on the platters, including the P-List (Primary Defect List), G-List (Grown Defect List), and the Translator module. These were found to be intact, confirming the physical platters and read/write heads had survived the electrical fault.

3. Hardware-Controlled Imaging: The drive was connected to a DeepSpar Disk Imager for a sector-by-sector clone. The imaging process was completed without incident, resulting in a full, binary image of the client's original 2TB drive on our secure storage array.

Phase 4: Data Extraction and Client Delivery

1. File System Parsing: The disk image was mounted in our recovery software. The NTFS file system was parsed, and the Master File Table ($MFT) was found to be fully intact. The complete directory structure and all files were accessible.

2. Data Integrity Verification: Checksums were verified on a sample of files against their $MFT records to guarantee a bit-for-bit accurate recovery.

3. Secure Data Transfer: All recovered data was written to a new, client-provided Seagate 2TB GoFlex External Hard Drive, ensuring the client received their data on a reliable, modern storage solution.

Conclusion

The client's Iomega drive failure was a compound issue involving a catastrophic electrical failure on the PCB (shorted TVS diode) and critical corruption of the unique firmware stored on the serial EEPROM chip. A simple PCB swap would have failed due to the firmware mismatch. Our success was predicated on a hybrid approach: performing component-level electronic repair and reconstructing the drive's firmware identity by programming a donor EEPROM chip with virgin modules from our technical database. This allowed the drive to initialise correctly, enabling a full, stable image of the undamaged user data.

The recovery was executed with a 100% success rate. All client data was restored with its original structure and integrity onto the new Seagate drive.

Swansea Data Recovery – 25 Years of Technical Excellence When your external drive suffers from complex electronic and firmware corruption, trust the UK's No.1 HDD and SSD recovery specialists. Our in-house PCB repair capabilities and extensive firmware database allow us to resolve failures that require both electronic and logical reconstruction. Contact us for a free diagnostic.

Case Study: Emergency Forensic Recovery from a LaCie 1TB Network Drive with Failed RAID 0 Stripe Configuration

Client Profile: A graphic design company using a LaCie 1TB Network Drive as their primary file storage NAS system. Presenting Issue: The LaCie device became unstable on the network, intermittently appearing and disappearing before failing entirely. When the client removed the two internal 500GB Samsung HD501LJ drives and connected them to a desktop via an external docking station, Windows Disk Management detected the physical drives but could not assign drive letters. The drives were invisible to both Windows Explorer and consumer data recovery software, rendering all business-critical graphic design files inaccessible.

The Fault Analysis

The client's symptoms pointed to a critical failure of the RAID 0 metadata structure, a common point of failure in consumer-grade NAS systems like the LaCie Big Disk.

1. RAID 0 Configuration Volatility: A RAID 0 (striping) array writes data sequentially across all member disks without parity. The "map" that defines how the data is interleaved—the stripe size, disk order, and data start offset—is stored in a proprietary metadata header on the drives themselves, typically in the first or last sectors. The intermittent connectivity suggested this metadata was becoming corrupted or unreadable by the LaCie's network controller.

2. Windows Invisibility Explained: When connected individually to a Windows PC, each drive contained only fragments of files and unrecognizable file system structures. Windows correctly identified the physical drives but could not parse a valid partition table or file system because the NTFS structures (Master File Table, Boot Sector) were split across both drives according to the RAID 0 algorithm. Without the correct parameters to virtually reassemble the array, the data was effectively gibberish to the operating system.

3. Underlying Physical Media Issues: The initial instability often indicates marginal sectors developing on one or both drives. As the NAS controller attempted to read the RAID metadata or user data from these unstable sectors, it would time out, causing the device to drop from the network. The client's attempts to force a connection via the docking station risked further logical corruption.

The Professional Data Recovery Laboratory Process

This scenario required a rapid, forensic approach to manually reconstruct the RAID 0 array in software, bypassing the failed LaCie hardware entirely.

Phase 1: Emergency Physical Drive Stabilization and Forensic Imaging

1. Drive Integrity Diagnostics: Both Samsung HD501LJ drives were connected to our PC-3000 system for individual diagnostics. We immediately read the S.M.A.R.T. (Self-Monitoring, Analysis, and Reporting Technology) data to check for physical pre-failure indicators like Reallocated Sector Count (0x05) and Current Pending Sector Count (0xC5).

2. Sector-Level Forensic Imaging: To preserve the evidence and prevent further stress on the drives, we created full, sector-by-sector clones of both drives using our DeepSpar Disk Imager. This hardware is specifically designed for unstable drives, employing adaptive read retry algorithms and timeout controls to gently negotiate any marginally readable sectors. A bad sector map was generated for each drive, logging any unrecoverable areas.

Phase 2: Empirical RAID Parameter Analysis and Virtual Reconstruction

With two complete forensic images, the core task of reverse-engineering the original RAID configuration began.

1. Block Pattern Analysis: Our specialized RAID recovery software performed a combinatorial block analysis across both disk images. It tested millions of potential combinations of stripe sizes (from 4KB to 1MB), disk orders (Drive A then B, or Drive B then A), and data offsets (to account for the LaCie metadata header).

2. File System Signature Validation: The correct configuration was empirically determined when the software, using a specific set of parameters (e.g., 64KB stripe size, specific disk order), detected a valid NTFS Boot Sector signature at the beginning of the resulting virtual volume. This confirmed we had successfully located the start of the logical volume.

3. Virtual Array Assembly: Using the deduced parameters, we built a virtual RAID 0 within our software. This process seamlessly interleaved the data from the two drive images according to the 64KB stripe size, outputting a single, coherent virtual disk file that represented the original 1TB volume.

Phase 3: File System Repair and Data Extraction

The final, reassembled virtual disk was processed for data recovery.

• NTFS Metadata Parsing: We mounted the virtual disk and parsed the NTFS file system. The Master File Table ($MFT) was traversed to rebuild the complete directory tree and file metadata. The client's large graphic design files (PSD, AI, INDD), which are often highly fragmented, were successfully reconnected.

• Data Integrity Verification: We performed checksum verification on recovered files to ensure a bit-for-bit accurate recovery, crucial for the client's professional graphic assets.

• Secure Data Delivery: All recovered data was transferred to a new, stable storage device for the client within the 24-hour emergency window.

Conclusion

The client's LaCie NAS failure was a critical logical corruption of the proprietary RAID 0 metadata, compounded by potential underlying media instability. The data was physically intact but logically inaccessible because the "map" needed to reassemble it was lost. A professional lab succeeds by completely bypassing the failed hardware, using forensic imaging to secure the raw data, and then employing sophisticated software to manually deduce the original storage parameters through empirical analysis. This process reconstructs the array virtually, rendering the original NAS enclosure irrelevant.

The recovery was executed with 100% success within the 24-hour emergency timeframe. All of the client's business-critical graphic design files were recovered with their original folder structure and file integrity fully intact.

Swansea Data Recovery – 25 Years of Technical Excellence When your NAS device fails and consumer-grade solutions prove ineffective, trust the UK's No.1 HDD and SSD recovery specialists. Our expertise in reverse-engineering proprietary RAID configurations and our investment in advanced forensic imaging technology allow us to recover data from complex storage systems that defy standard troubleshooting. We offer emergency service for business-critical data loss. Contact our engineers for a free diagnostic.