A video production house losing files to constant I/O errors, on an array the controller could no longer read cleanly — rebuilt outside the enclosure, from images, without a single write to the originals.
A video production company called after weeks of worsening symptoms on an eight-bay Inspur RAID 5. Copies stalled part-way, some exports played back with corruption partway through, and the array had begun dropping to an unresponsive state under load. The controller was still presenting the volume, which is precisely what makes this failure mode dangerous — the array looks alive, so people keep using it, and every pass over a weakening disk costs a little more.
Each disk was removed, labelled by bay and assessed individually before anything was powered as an array. Multiple members carried growing reallocated-sector counts, with unreadable sectors spread across several disks rather than concentrated on one. That distribution is the important detail: RAID 5 tolerates one failed member, but bad sectors scattered across several disks mean the parity needed to reconstruct any given stripe may itself be unreadable. The controller had also lost confidence in its own metadata, which is why performance had collapsed.
Nothing was rebuilt in the enclosure. Every disk was imaged read-only on hardware imagers, with per-head maps and adjustable timeouts so that weak areas were retried in short passes rather than hammered, and genuinely dead sectors were skipped and logged rather than allowed to stall the clone. From those images the array geometry — block size, disk order, parity rotation and offset — was derived by analysis rather than trusted from the controller, then the RAID 5 was assembled virtually. Where a stripe had an unreadable sector on one member, parity from the remaining members filled the gap; only stripes with two unreadable members could not be resolved.
The file system was rebuilt from the assembled volume and the production data checked by opening it, not merely by listing it — project files loaded in their editor, exports played end to end, and audio tracks and graphics assets confirmed against the folder structure the client recognised. Anything landing in an unresolved stripe was reported explicitly rather than quietly returned as a damaged file.
Around 98% of the array came back, including the active project timelines, rendered exports and the raw footage the studio could not have re-shot. The remaining shortfall sat in the small number of stripes where two members were unreadable in the same place — the honest limit of RAID 5 once bad sectors spread. The client was advised that an array showing I/O errors is already telling you it is failing, and that the correct response is to stop and image, not to keep working and hope.
Forcing a controller rebuild on an array with bad sectors across several members is the single most common way a recoverable RAID becomes an unrecoverable one: the rebuild writes to the disks, and where it cannot read parity it writes wrong data. Every array we take in is imaged read-only first and reconstructed from those copies, so the original disks are never altered. RAID, NAS and server work starts from £500 +VAT after a free 48-hour diagnostic and a written quote.
Get the device to us for a free diagnostic and a quick note on what went wrong — an engineer looks it over and puts your exact quote in writing before anything is started.
The route to your data starts with the device reaching us. Box it up securely, tuck your contact details inside, and send it across — after the free diagnostic, we put your exact price in writing before a single step is taken.
Sending it by post? Go with a tracked, insured service. Prefer to bring it round? Our door is open Monday to Friday, 9am to 5:30pm — just pack the device as described above beforehand.
Prefer to get a sense of things first? Complete the form with a bit more about the fault and an engineer will look it over and send back a tailored quote.
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Not by rebuilding it. Every member is imaged read-only first, then the array geometry — stripe size, disk order, parity rotation and offset — is re-derived from the data and the array assembled virtually from those copies. Parity fills any stripe where only one member is unreadable. Forcing a controller rebuild writes to the disks and is the most common way a recoverable array becomes an unrecoverable one.
RAID, NAS and server recovery starts from £500 plus VAT, fixed in a written quote after a free 48-hour diagnostic. Where drive-level physical work is needed we take a 50% deposit up front, with the balance payable only on a successful recovery.
Either works, but bay order is what matters. Label each disk with its bay number before removing it, and note the controller model if you can. Don't run a rebuild and don't re-insert a disk the controller has ejected.
Kick off with an instant online quote, or ring us and talk it through first. Either way you’ll know a clear, fixed price before any work starts.