Even though you've lost a mirrored pair due to two failed disks, a resync the wrong way or a failure inside the NAS enclosure where it was housed, that doesn't necessarily mean your data is lost. We image each drive individually and build the file system back up using what amounts to the best copy, and none of your originals are altered.
Every RAID case starts with a free diagnostic. Pricing is from £500 + VAT, priced per disk, and prior to starting recovery work we will provide you with a single written quote. On logical rebuilds, in most cases you only pay if we recover your data.
It would seem like having two identical copies should provide redundancy, but it doesn't always. Wear and tear on both disks of the pair, failure of the enclosure housing the mirror and incorrect resyncs in the wrong direction are common reasons why mirrors still come to our bench.
When mirror members are purchased as pairs, it is common for both of them to be run at the same time on the same storage unit. This can cause each member to wear down (and fail) together. Each member shares in the same heat load, surge load, and ageing process, so once one fails, it is likely that the second member will fail within days.
It is also very common for a dual bay NAS device, or a mirrored external disk set, to have the bridge board/controller fail before either of the two disks has failed. If the bridge board/controller fails, then even if neither of the two disks has experienced a failure, the user's data remains inaccessible until each disk is read directly and the original configuration is reconstructed.
Either you replace the wrong member or the box chooses poorly, and the empty (or stale) disk is copied over the correct (good) disk, which then erases the exact files you wanted the mirroring process to keep from harm.
If your mirror has been running degraded first on one disk and later on the other disk, it contains two separate and different versions of your data. If they are combined incorrectly, this will create corrupted data. When separated properly, both versions may be useful for recovery.
All types of data loss including deletion, corruption, ransomware and botched software updates are replicated in real-time to both members as soon as they occur. The replication process does not protect you from a type of damage known as "logical" damage.
Failed firmware or an operating-system fault on the NAS itself can render a perfectly healthy pair of drives bricked off until both are imaged and the volume rebuilt elsewhere.
The mirror is treated as two separate hard drives from the beginning. A copy of each member is created using a hardware imager, after bench repair of any physically failed drive, and then the contents of each image are compared to determine which contains the most complete, up-to-date information. Then the file system is rebuilt from that stronger copy, in a manner that draws on the second image wherever there are missing items. Once completed, your files are extracted without ever having written anything to either of the original drives.
A mirror will survive a single dead disk but everything else goes through it instantly. Deletions and corruption are copied over as soon as they occur, and ransomware will encrypt both halves of the mirror at the same time. If you lose an enclosure you'll lose access to the entire mirrored set. That is why a broken mirror constitutes a true recovery job. It is also why there is no such thing as "real" backups unless you have a duplicate of your data living on completely separate media somewhere else.
Most of the mirrors that we recover originate from the two-bay NAS devices (Synology, QNAP and Netgear) and small office servers, which have been sent in to us for data recovery by residents and businesses in Swansea, Neath, Port Talbot, Bridgend and Carmarthen. Before sending your disks, get a quotation first, and then post both disks, each labelled by its bay, to our Bristol address, tracked and insured. If preferred you may also drop off your disks at our Bristol location, Monday to Friday, 9am to 5:30pm, with no appointment needed. See our RAID recovery and NAS recovery services. Pricing is detailed on the data recovery cost page.
First, get a quote from us. Once we have provided you with a quote, please send us both drives and we will rebuild from the stronger copy. We also provide free diagnostics, followed by a fixed written quote.
First get a quote over the telephone or use our free on-line diagnostic. The majority of customers then have their media sent to us via post, this is tracked and insured.
Do you want to send a drive from your computer, laptop, MacBook, iMac, CCTV / DVR or server? Please do not send the complete unit of computer or device with a hard disk drive (HDD) or solid state drive (SSD) inside. Please remove it and only send the drive itself. For a server, please remove all disks and label them by their bay. We will also not perform removal of internal drives from devices in order to access data. Also, we will not extract data from devices where storage is soldered onto the motherboard (such as T2 and Apple Silicon Macs and some thin laptops). Additionally, we do not recover data from phones and tablets, only drives that can be removed and sent to us. If you're not sure which kind you have, ring us first.
↓ Print the booking-in & shipping form (PDF)
Clearly mark the parcel with the name Bristol Data Recovery, and when your media has been diagnosed we will call you immediately.
If unsure about what to post, please call us first on 0800 689 0668 (the free phone number), or complete a free online diagnostic.