and the customer couldn’t get at either. A My Book Duo keeps a live mirror of everything across its two disks; one of them failed, the other still held a spotless full copy — and it stayed locked away. This is the part of two-bay boxes nobody mentions.
← All case files · £300 + VAT, flat
A My Book Duo had gone silent, one of its two disks having given out. The whole point of RAID 1 is duplication — whatever lands on one disk is laid down, bit for bit, on its partner — so you’d fully expect the disk still standing to carry an entire, usable copy of the lot.
It was carrying exactly that. The trouble was that the enclosure wouldn’t hand it over.
A perfectly sound mirror disk can still be walled off from you by three separate things, and a cheap two-bay enclosure manages to stack up all three.
For one, the enclosure stamps its own RAID bookkeeping onto the disks, so lifting a member out and hanging it off a SATA port won’t just mount the partition — the drive’s layout is spelled out in headers that belong to the box. For another, encryption on the My Book Duo is done in hardware on the bridge board — the same trick a My Passport pulls, for the same motive — with the key living in the enclosure and not on the discs, so a disk on its own reads as static. And for a third, the controller simply won’t hand you one member by itself while the other is absent, which is the exact moment you’re asking it to.
The net of it: two whole copies of the data, each physically fine, and neither of them openable. None of that is a malfunction. It’s the way the device is designed to act.
properly dead, not just kicked out of the array.
holding a complete, byte-for-byte copy of the files.
which left nothing able to mount it.
All of this was handled off the enclosure. The intact disk was imaged by way of its own bridge, which let the built-in hardware decryption do its job as intended; we then took the enclosure’s RAID headers to work out how the mirror had been laid out, and reassembled the volume in software from that one decrypted image. Neither disk had a single byte written back to it.
Rebuilt off the surviving half of the mirror, the volume came back, and with it the studio’s work.
The deciding factor in a case like this was never the disk that failed — it’s whether the one left behind is genuinely sound and whether the bridge board survives the process. Where both members of a mirror have spent years silently accumulating bad sectors, the job is a good deal harder than it appears, precisely because owners treat redundancy as safety and never once put either disk under scrutiny.
There is precisely one disaster RAID 1 protects you from: a single disk dying. For everything else it does nothing at all, and it is no substitute for a backup.
Whatever you get wrong, a mirror gets wrong too, instantly and to the letter. A deleted file disappears from both disks together; ransomware seizes the pair; one surge through the enclosure claims them both; knock the unit off the desk and the two hit the floor as one. Nothing earlier is kept and nothing can be undone — there’s only your data, written twice, inside a single box sitting on a single desk.
Anything that genuinely matters needs a second copy somewhere else entirely. And on the day the enclosure itself dies, post the entire unit with both disks still in it — remember that the bridge board holds your encryption key.
Drop the drive at our Guildford Business Park reception, or post it to us — it costs nothing to find out what happened. You get a written figure from the fixed bands before any work begins.