Data Recovery Case File · NAS & RAID · Mechanical / Firmware

Synology NAS drive not detected: a WD Red Pro reporting 0GB — and the RAID 1 mirror that mattered more

A two-bay office NAS was picked up and laid flat, running, by a visiting contractor. One drive was never screwed into its caddy; the movement unseated it mid-operation. Afterwards the NAS rejected it, and on a bench test it identified by name and serial number but reported 0GB. This case is as much about recovery judgement as recovery technique.

The enquiry

“The NAS was moved from vertical to horizontal by hand while running. One HDD wasn't secured with screws and came slightly out of the board. After reseating it, the NAS doesn't find it. In the BIOS we see the name and serial number but the size shows 0GB. It spins up, and there's a very light tick. We can't see any damage on the PCB.”

Reading the symptom

A drive that reports its model and serial but 0GB has told you something precise. Model and serial come from the ROM on the PCB — the drive can recite those with no help from its platters. Capacity requires the drive to load its firmware modules from the service area on the platters and initialise its translator. "Correct name, zero size" therefore means: electronics alive, service area unreadable — either because the interrupted hot-unplug corrupted firmware data mid-write, or because the head that reads the service area was damaged in the event. The light ticking pointed toward the second. Either way, this drive needed firmware-level and possibly clean-bench work.

The decision that shaped the job

But this was a RAID 1 — a live mirror. Every block on the failed drive had a twin on its healthy partner, current to the moment of the incident. So before any work began on the damaged member, the healthy drive was imaged in full on the Atola TaskForce 2 — write-protected, hardware-imaged, untouched by any further NAS boot that might resync, rebuild or otherwise "help." From that image the Synology volume structure was assembled — the standard DSM layout of system and swap partitions ahead of the data partition, with the md metadata read from the image rather than trusted to a degraded NAS — and the customer's shared folders mounted, extracted and verified.

That resolved the actual problem: the office had its data. The 0GB drive then became a question rather than an emergency, and it's a question we put to the customer honestly — a firmware repair on the damaged member via the PC-3000 was available, but with a verified full recovery already delivered from the mirror, it would be work purchased for a drive that should in any case be replaced rather than trusted again. They took the data and a pair of new drives.

Outcome

Full recovery of the volume from the mirror member; the damaged drive retired without further spend. Two footnotes earned their place in this case file. First, the customer's instinct to power everything down quickly was exactly right — a degraded array left running is an array one further failure from disaster. Second: this good outcome existed because the array was genuinely redundant. RAID 1 saved this office. It would not have saved them from deletion, ransomware or theft — a mirror is not a backup, it's just two copies of the present moment.

Our case files are drawn from genuine enquiries received by our laboratory over the past ten years, anonymised to protect client confidentiality. Each one describes the diagnostic and recovery procedure our engineers apply to that fault, using the equipment listed.