RAID recovery – A Necessary Evil

Data has become one of the most important assets a business (or even a consumer) owns, so its protection is vital. Loss, theft or corruption of information can even threaten the future of a business, through loss of earnings, stolen intellectual property or even prosecution in some countries.

To counter this threat, organizations have a range of options designed to protect data. Tape and disk backup regimes, Cloud replication and shadow file copies all bring the power of software to keep information safe. But data protection begins at the hardware level using RAID arrays, groups of disks configured to improve system performance and protect against hardware failure that would typically result in data loss in a single-disk system.

RAID arrays may sound like enterprise class technology, but they are becoming increasingly common as the cost of storage falls – even those self contained network attached storage (NAS) devices aimed at consumers tend to implement some form of RAID array to protect data.

Why is RAID important for data protection?

Normally if the hard drive in your computer fails, your data is inaccessible and could be lost permanently (or until you can perform some low level file recovery on it anyway). With a RAID array, data is replicated between several drives so that if one of them breaks down, the information is not only available on the remaining drives, but the system will continue to run even with a broken drive.

So what’s the problem?

Depending on how the RAID array has been configured, it will survive at least one drive failure, possibly more. But what if all of the drives fail? Or a critical index becomes corrupted and written across each drive, making chunks of data inaccessible?

The short answer is that the RAID array fails completely and the data is, on the face of it, lost. In large businesses, RAID array data would be replicated elsewhere for “proper” backup, allowing for a full system rebuild in this scenario. But for small businesses or consumers, they are unlikely to have any such system in place for their network attached storage devices.

Low level disk recovery tools can usually help you get back the data you need with a minimum of fuss in a single disk environment. But when dealing with a RAID array, recovering data is a complex job best left to professionals. For instance, Kroll Ontrack does RAID recovery by taking the drives to their specialist labs and stripping the hardware back to extract the disk platters. These are then manually cloned, block-by-block onto new drives before the array is rebuilt from scratch. This painstaking process ensures that not only is the ‘lost’ data recovered, but that it is ready to be used immediately.

And unfortunately there is no other way to recover data from a completely failed array.

Plan ahead

Although it is encouraging to hear that the impossible can be achieved, recovering data from a completely failed RAID array, you should plan ahead to avoid this situation. Check to see whether there is a Cloud-replication option built into your NAS system which can take automated, offsite snapshots – these are much faster and easier to recover than the rebuild process described above!

So despite the potential for hardware-related headaches, RAID should be your first line of defence in protecting your data against loss.