When a fire ripped through a British businessman’s private island a few months ago (we can't name him, but we're sure you can guess who it is), several of his hard drives were caught up in the 200ft-high blaze.They contained crucial data that he needed to recover.

Kroll Ontrack, working from its data recovery lab in Epsom, Surrey, was brought in to help recover as much of valuable data as possible from the drives. The damaged items included eight drives from two servers configured in two sets of four-disk RAID 5 arrays.

Robert Winter led the recovery of the data, which started in late 2011 and worked with his team to prioritise the devices that contained the most precious information.

As the images here show, the drives had been severely damaged, and look like a complete write-off. Not only were they burned in the fire, but they were then flooded by water from the fire hoses. This led to corrosion - something you really don't want inside your hard disks.

In their clean room, Ontrack engineers were able to disassemble the drives and clean up the platters which contain the data. Even smoke particles can prevent data being read, so have to be removed. The team replaced the damaged components, such as read/write heads, with brand-new ones and rebuilt the disk drives one at a time.

The next stage of the recovery was to attempt to read the raw data off the drives, and six of the eight disk drives were fully recovered. This then left the challenge of reconstructing the missing data from the two unrecoverable drives. 

Fortunately, the RAID 5 configuration makes this possible thanks to data redundancy. With the assistance of Kroll Ontrack’s proprietary software and in-depth RAID configuration knowledge, the engineers were able to create a virtual RAID, rebuild the data from the missing disks and then extract the files.

In the end, 100 per cent of the data was successfully recovered. The data was written back to new disks which were then returned to their happy owner.

HP hard disk fire damage

Every disk from the Raid array was damaged by fire

Water damage to disk

Corrosion from the water used to extinguish the fire also damaged the disk and made the recovery more complex.

Corroded disk platters

Kroll Ontrack engineers opened the case to look at the damage inside and clean it.

Damaged read write heads from disk

The damage inside the device is extensive, preventing the disks from functioning.

Read write heads had to be replaced

The engineers replaced the damaged components with new ones to enable to disks to function again.