Synology NAS, 4-disk Spanned Storage Pool, Two Disk Failures.

A spanned storage pool (or JBOD – Just a Bunch Of Disks) writes data sequentially across all disks in the set. Unlike RAID 4 or 5, it does not contain any distributed parity or redundancy information. The failure of a single disk will result in the loss of all data from that point onward in the span. The failure of a second disk compounds the problem, making the entire logical volume inaccessible through normal means. The Synology operating system (DSM) will correctly report a critical failure and offer no rebuild option, as there is no redundancy to rebuild from.

Our data recovery process is designed to address this exact type of complex, multi-disk failure.

Our Data Recovery Methodology for Multi-Disk Spans

Stage 1: Initial Diagnosis and Disk Integrity Assessment

Upon receipt of your Synology NAS or the individual disks, our first step is a physical and logical assessment.

1. Physical Inspection & Stabilisation: Each of the four hard drives is connected to our proprietary hardware imaging tools. We perform a thorough physical and electronic inspection. If a drive has physical issues (e.g., seized motor, degraded read/write heads, PCB damage), we will stabilise the device to facilitate a safe data extraction. This may involve procedures such as PCB repair or head stack assembly replacement using compatible donor parts.

2. Sector-by-Sector Imaging: The cornerstone of our recovery process is creating a complete, sector-by-sector image of each accessible drive. For the failed drives, this is a critical and delicate operation. Our tools use specialised techniques to read around bad sectors, manage unstable drive behaviour, and extract the maximum possible amount of raw data from the platters. This process results in four complete image files, which become our new, stable working copies. All subsequent work is performed on these images, preserving the original drives in their received state.

Stage 2: Logical Analysis and Spanned Set Reconstruction

This is the most technically complex phase of the recovery.

1. File System Analysis: We analysed the individual disk images to determine the on-disk data structure. Synology typically uses the Btrfs or ext4 file system on top of its Logical Volume Manager (LVM) and software RAID/mdadm layers. We need to reverse-engineer the parameters of the spanned set.

2. Determining Span Parameters: A spanned set concatenates the disks. Our engineers use specialist data recovery software and hexadecimal editors to examine the images and identify key metadata. We need to ascertain:

   • The order of the disks within the span.

   • The offset where each disk’s data begins and ends.

   • The stripe size (chunk size) of the span, which is typically sequential but must be verified.

3. Virtual Reassembly: Using the determined parameters, we create a virtual reconstruction of the original spanned set within our secure data recovery environment. This involves programmatically stitching the four disk images together in the correct order to form a single, cohesive logical volume image. This virtual volume does not rely on the original hardware.

Stage 3: File System Repair and Data Extraction

The virtual volume will likely have a severely corrupted file system due to the dual-disk failure.

1. Metadata Carving and Repair: The file system’s metadata (the “table of contents” pointing to the files) is often fragmented across the span and will be partially lost. Our engineers employ advanced techniques to scan the entire virtual volume for surviving metadata structures. We piece these together to rebuild a functional directory tree.

2. Data Carving (Content-Aware Recovery): Where file system metadata is irrecoverable, we utilise content-aware carving. This technique scans the raw data stream within the virtual image for specific file signatures (file headers and footers). Given the content includes X-ray images (which may be in formats like DICOM), our tools are configured to identify and reconstruct these files based on their unique data patterns, even without directory information.

3. Data Verification and Integrity Checking: Recovered files, especially the critical X-ray images, are checked for integrity. We verify that the file structure is sound and, where possible, that the files can be opened and are not corrupt.

Stage 4: Data Return and Client Review

Once the recovery is complete, we provide you with a secure link to a listing of all recoverable data. You can review this list to confirm the success of the recovery, particularly for the patient X-ray databases, before we proceed to copy the data to a new storage device of your choice, such as an external hard drive.

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Our Data Recovery Services

We offer a comprehensive and specialised data recovery service for all NAS (Network Attached Storage) devices, including complex multi-disk configurations from Synology, QNAP, Netgear, and other manufacturers.

• NAS & Server Recovery: Specialised recovery from all RAID levels (0, 1, 5, 6, 10, 50, 60) and JBOD/Spanned sets.

• Hard Drive Recovery: Recovery from all interfaces including SATA, SAS, SCSI, and FC (Fibre Channel).

• Solid State Drive (SSD) Recovery: Advanced recovery from failed SSDs, including those with controller or flash memory issues.

• Virtual Machine Recovery: Expertise in recovering corrupted virtual disks from VMware (VMDK), Hyper-V (VHD/VHDX), and others.

• Encrypted Drive Recovery: Solutions for recovering data from hardware and software-encrypted drives where the password or key is lost.

Supported Systems & Storage Devices

We possess the expertise and technology to recover data from a vast range of systems:

• NAS Devices: Synology, QNAP, Netgear ReadyNAS, Western Digital My Cloud, Asustor, Drobo.

• Operating Systems: Windows (all versions), macOS, Linux, and Unix.

• File Systems: NTFS, FAT32, exFAT, HFS+, APFS, ext3, ext4, Btrfs, ZFS.

• Storage Media: Hard Disk Drives (HDDs), Solid State Drives (SSDs), RAID arrays, SANs, SD cards, and USB flash drives.

Why Choose Sheffield Data Recovery?

• 25 Years of Specialist Experience: Our long history is a testament to our technical expertise and trusted reputation. We have successfully recovered data from thousands of complex scenarios, including multi-disk NAS failures.

• Proprietary Tools & Methods: We combine commercial-grade data recovery software with our own developed techniques and hardware, giving us a unique capability to solve problems that others cannot.

• No Recovery, No Fee Policy: We provide a free evaluation and quote. You only pay if we are successful in recovering your critical data.

• Certified Secure Service: We understand the sensitivity of your data, especially patient X-ray images which fall under GDPR and medical confidentiality guidelines. Our facility and processes are designed to ensure complete data security and privacy throughout the recovery journey.

• UK-Based Technical Experts: All recovery work is performed in-house by our engineers in Sheffield. You can speak directly with the technical team working on your case, ensuring clear communication and a full understanding of the process.

If your dental practice is facing a data crisis with its Synology NAS, please contact our technical team for a confidential and free initial assessment. We are here to provide the expert assistance you require.