A RAID 5 array that has dropped a disk, failed a rebuild or lost its controller can look catastrophic, but the data is most likely recoverable: we image each member drive and then virtually rebuild the array, without writing anything to any of the original disks.
Free diagnostic service with every RAID recovery project. Once an initial diagnosis has been completed, a fixed price is always quoted in writing before any work begins. Our RAID recovery prices start at £500 + VAT, based on the number of disks involved, and on logical rebuilds you only pay if we recover your data.
RAID 5 can survive losing one disk, but only one. These are the failures that bring an array to our bench.
A RAID 5 array can tolerate losing one disk; however, once you replace the failed disk, the rebuild puts hours of heavy wear on the ageing disks that remain. That is why it is so common for a second disk to fail in the middle of the rebuild, turning a recoverable array into an emergency.
When a RAID controller, HBA or backplane fails, the entire array can be taken offline even though all of the disks are still functioning properly. There is no way to access the data until the configuration and parity metadata have been read, which then allows the volume to be rebuilt.
Once a disk drops out and the array runs degraded, that disk goes stale. Attempting to force it back into the array later will mix old data with new, corrupting the parity information across all members of the set.
When there are at least two members of the RAID that have unnoticed bad sectors, parity will never be able to protect all stripes. We create an image of each of those drives, working around the damage, prior to doing any form of array rebuild.
Re-creating the array, initialising it, or even a "fix" attempt started from the array's dashboard will likely wipe out the metadata that describes how your data is organised.
A capacity expansion or RAID-level migration that stalls part-way leaves the array in an inconsistent state that won't mount.
We never work directly on customers' original disks. Each member drive is imaged using dedicated hardware imagers, and any physically failing disk is repaired on our repair bench first. From those images we determine the exact configuration (disk order, block size, rotation and parity direction) so that a virtual rebuild of the RAID can take place. Your data is then extracted from this virtual rebuild without modifying the original disks, which remain available as a fallback.
When a RAID 5 fails, many people install a replacement disk and let the controller rebuild the array. However, on an array that has already lost its redundancy, that rebuild places an extreme amount of extra load on the remaining drives at their most vulnerable time, and should another failure occur part-way through, a relatively simple recovery becomes far more complicated. If the rebuild has already failed, power the system down and don't retry it.
Most of the RAID 5 systems we recover serve as the primary storage for a small-business server or NAS. We support Dell PowerEdge, HP ProLiant, Lenovo and custom-built servers, as well as NAS boxes from Synology, QNAP and Netgear, for businesses across Surrey and west London. All media is posted in to our Guildford location, and urgent business cases can be prioritised. See our general RAID recovery service, NAS recovery and typical data recovery costs.
We offer a free diagnostic and a fixed price quotation, and on logical rebuilds, you only pay if we recover your data. Start now, or ring our freephone number.
Before sending anything, get a quote from us either by telephone or using our free online diagnostic. Then post your hardware to us (tracked and insured), or drop it off at our Guildford laboratory in person.
Sending a drive from a computer, laptop, MacBook, iMac, CCTV/DVR or server? You will need to remove the internal hard drive or SSD and send us just the drive, as we are unable to remove the drive for you. We also cannot recover storage soldered onto a motherboard, such as in Apple Silicon Macs and some thin laptops. Only drives that can be removed from a machine and sent to us can be recovered. If you are unsure whether your device has a removable drive, please call us before sending. RAID, server and SAN drives need to be removed from their enclosure and labelled by bay. For a NAS, send the disks themselves if they are removable, otherwise the entire NAS device. An external single drive should come to us whole, along with its cable and power supply.
↓ Print the booking-in & shipping form (PDF)
Please mark the package for the attention of Guildford Data Recovery, and we will call you as soon as we have diagnosed your media.
Unsure as to how to proceed with sending the item in for recovery? Then simply call 0800 689 0668, or complete the free online diagnostic prior to dispatching the item to obtain your price quotation.