RAID / NAS data recovery – logical and physical failures
RAID (Redundant Array of Independent Disks) increases performance and availability, but it does not eliminate the risk of data loss. When a RAID or NAS system fails, incorrect actions (rebuilds, initialization, changing disk order) can quickly make the situation worse.
At SGDATA we recover data from RAID 0/1/5/6/10 and NAS devices (Synology, QNAP and many others) in a safe and controlled way. We always start by cloning the disks and work only on copies – this is the key to safe RAID data recovery.
If your server, NAS or RAID volume has disappeared, do not start a rebuild and do not create new volumes. Power the system down and contact us first.
Supported RAID and NAS configurations
- RAID levels: RAID 0, RAID 1, RAID 5, RAID 6, RAID 10 (1+0), RAID 01 (0+1)
- JBOD and single disks from storage pools
- NAS devices: Synology, QNAP, WD, Seagate, Asustor, TerraMaster and others
- Software RAID: Linux mdadm, LVM, Windows dynamic disks
- File systems: EXT4, Btrfs, XFS, NTFS, exFAT (and other common formats)
Typical causes of RAID / NAS failures
- Failure of one or multiple disks in the array
- Errors during firmware update, RAID rebuild or migration
- Controller or NAS mainboard failure
- Power outages, brownouts and surges
- Accidental deletion of a volume or initialization of a storage pool
- Interrupted, incorrect or repeated rebuild attempts
- Fire, flood or other physical damage to the equipment
- Unsuccessful “do it yourself” recovery attempts and experiments
What to do – and what to avoid
✅ Recommended actions
- Power the NAS/server off and label the disks according to their slots.
- Write down the model of the device and known configuration (RAID level, disk sizes, number of disks).
- Send all disks from the array, including those that appear to be working.
- Provide passwords or encryption keys if volume encryption was used.
❌ Things to avoid
- Starting a rebuild on degraded or failing disks.
- Changing the order of disks in the NAS or mixing disks from different sets.
- Running firmware updates after a failure.
- Creating new volumes or storage pools on the same disks.
- Testing different configurations “by trial and error” in RAID controllers.
How our RAID / NAS data recovery process works
- Receiving the equipment – you can send just the disks or the entire NAS / controller with all drives.
- Expert analysis – we create sector-by-sector clones of the disks and analyse RAID metadata and the file system structures.
- Report and quotation – you receive an estimated recovery scope, list of data (or its sample) and a clear price.
- Virtual reconstruction – we rebuild the RAID configuration in a controlled, virtual environment and extract data to a new storage device.
- Verification and delivery – after internal checks the recovered data is returned to you on a new disk or other agreed media.
Which RAID configurations are the most challenging?
RAID 0 – no redundancy at all. Failure of a single disk breaks the data stream. Recovery is possible, but very sensitive to further damage and attempted rebuilds.
RAID 5 / RAID 6 – redundancy allows one (RAID 5) or two (RAID 6) disks to fail, but incorrect or incomplete rebuilds can heavily mix data and parity blocks. In such cases we reconstruct the correct layout from metadata and clones.
RAID 10 – usually offers good redundancy. Recovery is often possible as long as the number and placement of failed disks does not exceed the redundancy of the array.
Price range (approximate)
Every RAID case is different – final cost depends on the number of disks, type of damage and time required for analysis and reconstruction. Below values are only indicative and usually refer to PLN (Polish customers):
- Logical damage (RAID 0/1/5/6/10) – approx. 400 PLN per disk Reconstruction of RAID parameters and virtual assembly of the volume.
- Physical damage (single disks from the array) – from 1000 PLN Diagnosis and repair/read-out of the failed disk, head or electronics issues.
- Advanced, multi-disk arrays – around 900 PLN per disk Non-standard layouts, mixed disk sizes, complex or badly rebuilt arrays.
Diagnosis is usually free of charge for drives that have not been opened by third parties before. For previously opened drives, charges apply according to the price list. You always receive a quotation and can decide whether to proceed.
FAQ – Frequently asked questions
Do I have to send all disks from the array?
Yes. Even “healthy” disks contain important RAID metadata and are critical for correct reconstruction. Sending only one or two failed disks usually makes proper analysis impossible.
The array started to rebuild and then stopped – what should I do?
Power the device off and contact us. Continuing a failed rebuild attempt can mix data and parity blocks, making recovery much more difficult or sometimes impossible.
Can I send just the controller or the whole NAS instead of separate disks?
You can send the entire NAS or server, but please always include all drives. If possible, describe the original disk order in slots (1, 2, 3…). This greatly speeds up analysis.
Cooperation with IT service providers and companies
For more than 11 years SGDATA has been working with computer repair shops, IT companies and network administrators. We provide specialist support in recovering data from RAID arrays, NAS devices and file servers.
- Priority diagnostics without waiting in the standard queue
- Partner pricing and discounts for regular cooperation
- White-label option – reports and documentation under your brand
- Full confidentiality of client data and NDAs where required
If you would like to offer professional RAID/NAS data recovery to your customers without investing in your own lab, feel free to contact us for partnership details.