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// case file · RAID 5 · 4 disks · controller firmware

The disks were fine. The card had forgotten them.

A firmware update on a RAID controller completed, rebooted, and presented an empty array. Every disk was healthy, every byte was intact, and the only thing missing was the description of how they fitted together.

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Device

RAID 5, 6 × 4 TB SATA

Failure

Controller firmware update

Complication

No on-disk configuration retained

Outcome

Full recovery, 5 days

// the brief

What arrived, and what was at stake.

An surveying practice lost access to its project server after a routine controller firmware update. The card came back reporting no configured arrays and offering to create a new one — which, had anyone accepted, would have ended the job before it started.

On the volume sat live project files, drawing archives and the practice’s document management database. No disk had failed. The array had simply ceased to exist as far as the controller was concerned.

// on the bench

What the diagnosis found.

01

All six disks passed health checks

no reallocated sectors of consequence, no mechanical symptoms, and full capacity reported by each.

02

Parity was intact on the platters

meaning a complete reconstruction was arithmetically possible rather than merely hopeful.

03

The controller retained nothing usable

the update had cleared its configuration, and this card family does not write a redundant copy back to the members in a recoverable form.

The temptation here is obvious: accept the card’s offer to create the array and hope it lands on the original layout. On many controllers creating an array initialises it, and initialisation writes — which would have overwritten the structures needed to work out the geometry in the first place.

// the recovery

How it was done.

Each disk was imaged read-only before any analysis, and all subsequent work ran against those copies. The geometry was then derived from the data itself: stripe boundaries located by looking for structural repetition across members, disk order established by testing candidate permutations against known NTFS structures, and parity rotation and offset confirmed by verifying that reconstructed stripes produced valid metadata rather than noise.

With the layout proven rather than assumed, the RAID 5 was assembled virtually and the file system mounted from the assembled volume — entirely outside the controller that had caused the problem.

// outcome

What came back.

Everything. Six healthy disks, intact parity and only the map missing meant a complete recovery, with folder structure and filenames preserved throughout.

The document management database was checked for structural consistency rather than simply copied, and project files were opened in their applications before the set was returned on fresh media.

// the transferable bit

What to take from this.

A lost configuration is not lost data. When a controller forgets an array the contents are still on the disks exactly as they were — what has gone is the description of how to read them, and that can be reconstructed by analysis.

The thing that turns this into an unrecoverable job is what happens next. Don’t create, initialise or re-scan the array to see whether it comes back. Power the server down, keep the disks in bay order, and note the controller model. Server and RAID recovery starts from £500 +VAT after a free 48-hour diagnostic.

// read next

Related.

// your turn

Lost something that matters? Free diagnosis, a fixed price, and no fix, no fee.

Bring the drive to our Oxford Science Park reception, or post it over — it costs nothing to learn what went wrong. You’ll have a written price from our fixed bands before any work starts.