Data Recovery Case File · NAS & Network Storage · One Question Decides Everything
The Surviving Disk Either Holds Everything or Holds Half of It
His enquiry gives every detail except the one that matters. A dropped 3TB disk from a two-bay network unit, where "the other disk is functional. Is there a chance to repair the disk, or to recover the data to another drive just like it for further use?" A two-bay unit can be arranged in ways that make the surviving disk a complete copy or a useless half, and until that is established nothing sensible can be said about cost, urgency or prospects.
| Media | 3TB disk from a two-bay network unit following a fall — companion disk functional; array configuration not stated |
| Reported situation | Disk dropped and no longer functioning · disk forming part of a two-bay network unit · companion disk reported as functional · configuration of the unit not stated · owner seeking both data recovery and restoration of the unit to service |
| Fault class | Impact damage to one member with configuration undetermined — surviving member holding complete or partial content depending on arrangement |
| Equipment used | Unit configuration established from the surviving member before any work · dropped member kept out of the unit throughout · surviving member imaged write-blocked before any rebuild was contemplated · dropped member assessed independently where its content proved necessary |
The decode: three arrangements and three different situations
If the unit was mirrored: both disks held identical copies of everything. The surviving disk contains the complete contents, and this is not a recovery at all — it is replacing a failed member, which is exactly what the arrangement exists to make possible. His data is already safe and he does not yet know it.
If the unit was striped: every file was split across both disks. The dropped one holds half of everything, and nothing on the survivor is usable on its own — so the damaged disk must be recovered, and it is a serious case rather than a routine replacement.
If the two disks were independent volumes: only what lived on the dropped disk is affected, and the survivor is simply unaffected. A common arrangement and the least discussed.
Why the same enquiry covers all three: the unit presents shares, and the person using it sees folders rather than disks. The configuration was chosen once during setup, possibly years ago, and never thought about since.
How to establish it without any special knowledge: compare the total capacity the unit reported against the capacity of the disks. Two 3TB disks presenting about 3TB is a mirror; presenting about 6TB is a stripe; presenting two separate volumes is independent. That single figure answers it, and the unit's own interface will state the arrangement directly.
Why it matters before anything is touched: if it is a mirror, the correct action is to image the survivor and then replace the failed disk. If it is a stripe, the correct action is to touch nothing and assess the dropped disk, because a rebuild would be impossible and any attempt to bring the volume up risks the survivor.
Why the dropped disk must not go back in the unit either way: a unit meeting a member it recognises may attempt to rebuild or resynchronise. On a dropped disk that means reading a damaged mechanism at sustained load, which is the one operation to avoid.
Why his two goals should be separated: recovering the data and returning the unit to service are different jobs with different urgency. The data comes first, and the unit can be rebuilt afterwards from a position of safety.
On the bench
The unit configuration was established from the surviving member before any work — a mirrored arrangement leaving the survivor holding complete content, a striped one leaving it holding alternating fragments of every file, and independent volumes leaving it unaffected, which are three materially different situations. The dropped member was kept out of the unit throughout, a unit recognising a returned member potentially attempting resynchronisation. The surviving member was imaged write-blocked before any rebuild was contemplated.
The outcome
Configuration established before any work, the dropped disk kept out of the unit, and the survivor imaged before any rebuild was contemplated. Free assessment, one fixed written figure including VAT, 50% of parts and labour upfront with the balance only on successful recovery. The decode: compare the capacity your unit reported against the size of the disks. Two 3TB disks presenting around 3TB means each held everything, and your data is already safe on the survivor. Presenting around 6TB means the dropped disk holds half of every file.
One disk failed in a two-bay unit
Find out how it was configured before doing anything, and don't put the failed disk back in. Compare the total capacity the unit reported against the size of the disks: two 3TB disks presenting about 3TB means they mirrored each other, so the survivor holds everything and you need a replacement rather than a recovery. Presenting about 6TB means every file was split across both, so the failed disk holds half of everything and matters enormously. Two separate volumes means only what lived on the failed disk is affected. The unit's own interface will state it. And a unit meeting a returned member may try to resynchronise.
Check the configuration first — then call Oxford Data Recovery on 01865 593000; arrangement established before any work, failed member kept out of the unit, survivor imaged before any rebuild is contemplated.
Request a quote online →
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.