Most NAS units run standard Linux software RAID behind a deliberately closed interface, which is why a dead appliance is usually a better prospect than it looks — the disks are healthy and the obstacle is the box. We image every member and reassemble the array, the pool and the file system entirely outside the unit.
$ bdr diagnose /dev/nas → NAS: Synology DS920+ · 4 × 4 TB · SHR → Status: VOLUME CRASHED — disk dropped, Btrfs damaged → Client: confidential · Oxford OX2 $ bdr engineer-working → Member disks: all 4 imaged read-only → SHR + LVM: reassembled off the box → Btrfs: repaired · volume mounted $ bdr verify → ✓ shares — 11.2 TB → ✓ photos + backups — restored → ✓ NAS recovered — data back
A disk the unit has dropped may still hold most of its data. Putting it back can start a resync in the wrong direction, overwriting the good copy with the stale one — and on a degraded array there is no redundancy left to absorb that.
Which is why “not accessible” can mean four different things, and they need opposite responses.
This is the reason a dead NAS is usually a better prospect than it looks.
Synology, QNAP, Buffalo, Netgear, Terramaster and most others run conventional Linux software RAID — mdadm — with an LVM pool above it and ext4 or Btrfs on top. Nothing about that is proprietary, so once the disks are imaged the reconstruction is well understood and the appliance can be removed from the equation entirely.
The exceptions are worth naming: Synology SHR is a layered mdadm arrangement that has to be reassembled in the right order, QNAP frequently adds thin provisioning whose metadata must be walked to locate real extents, and Drobo BeyondRAID is genuinely proprietary and must be derived from the images. All are recoverable; they simply need the layers taken in order. Guide: QNAP NAS data recovery.
The unit is never asked to repair, rebuild or mount anything.
Bay order is central to reconstruction. If it has already been lost we can usually establish it by analysis, but labelling saves time and cost.
Including any disk the unit ejected, which frequently still holds readable data.
Chunk size, member order, parity layout and data offset derived directly rather than trusted from superblocks that may be stale.
LVM, SHR layering or thin-provisioning metadata walked in order to locate the real extents holding your data.
ext4 or Btrfs reconstructed from the assembled volume, with files opened to verify rather than merely counted.
Priced by the reconstruction, not the capacity.
NAS, RAID and server recovery starts from £500 +VAT, confirmed after a free 48-hour diagnostic. Physical drive-level work carries a 50% deposit with the balance payable only on success.
Send the whole unit or the disks in bay order — both are fine. Tell us the model, the RAID level if you know it, and whether a rebuild or repair was attempted. Full write-ups: a Drobo with two dead disks and a grinding noise, QNAP Recovery: RAID 5 Reconfigured as RAID 0 and Synology RAID 5 Recovery: Two Drives Grinding. Also: a Buffalo LinkStation shedding sectors.
Send the NAS in for its free diagnostic with the make, bay count and RAID type; an engineer assesses it and confirms the exact quote in writing before any work starts.
Getting your data back starts with getting the NAS — or all its disks — to us. Pack it safely, label the bay order if sending disks, enclose your contact details, and once we've run the free diagnostic we confirm your exact quote in writing before any work begins.
Posting it? A tracked, insured service is what we’d recommend. Rather drop it in? You’re welcome Monday to Friday, 9am to 5:30pm — just package the device up as above first.
Need a scoped quote first? Describe the NAS, RAID type and fault on the form and an engineer will assess it and reply with a tailored quote.
We’ll be in touch shortly. If it’s urgent, call 01865 593000.
The questions we’re asked most about recovering data from a NAS.
Copy your data off immediately, before attempting any repair. Degraded means a member has dropped but the volume is still readable, and that window is the cheapest recovery available. Don’t start a rebuild until the data is safe elsewhere.
Usually easily. Most units run standard Linux software RAID with an LVM pool on top, so once the disks are imaged the array can be reassembled entirely outside the appliance. A dead NAS is often a better prospect than it appears.
Either works. If you send disks alone, label each with its bay number first — that order matters for reconstruction. Don’t reinsert a disk the unit ejected and don’t let a rebuild run beforehand.
Yes. SHR is layered mdadm that must be reassembled in the correct order, and QNAP thin provisioning needs its metadata walked to find the real extents. Both are recoverable — they simply require the layers taken in sequence.
Possibly not at all. Windows disabling SMBv1 orphaned many older units, which then present exactly like a failure while being entirely healthy. Check whether the admin interface still loads before assuming the worst.
From £500 plus VAT, fixed in a written quote after a free 48-hour diagnostic. Where a member needs physical drive-level work there is a 50% deposit, with the balance due only on success.
Free to diagnose, priced on a clear tier from £500, and no fix no fee on the majority of jobs — whatever the badge, Synology, QNAP or otherwise, we bring the data back off the box. Get your recovery moving today.