RAID Data Recovery Services.
RAID is becoming more common as a preferred method of storage. As hard disk drives have become cheaper and raid controllers are now built-in on many computer systems we are getting more requests to quote for RAID data recovery. Over the years as demand has increased our capacity to recover from RAID systems has increased accordingly. Below the image are details of some of the most common RAID we have seen. There are other raid levels for example RAID 10 and RAID 51, etc but these are variations on those listed below.
- RAID 0
Consists of at least two drives with data stored in 'stripes' spread through out the drive
- RAID 1
Two drives each containing the same data - the second being a direct copy of the first.
- RAID 4
At least three drives. The last drive contains a Parity block (P) calculated from the blocks of the previous drives. for example if you have 4 drives numbered 1,2,3,4 with 4 as a parity drive then this would be calculated as 1 XOR 2 XOR 3 with the result stored on 4. If a single drive fails then the missing data can be calculated .. for example if drive 1 fails its data can be calculated by 2 XOR 3 XOR 4.
Stripe 1: 1 2 3 P
Stripe 2: 4 5 6 P
Stripe 3: 7 8 9 P
- RAID 5
Also needs at least three drives, this time the parity 'rotates' through the drives. For example
Stripe 1: 1 2 P
Stripe 2: 3 P 4
Stripe 3: P 5 6
Parity is calculated in the same way as RAID 4 and so any missing drive can have its data rebuilt by applying the parity formula.
- RAID 6
Needs at least 4 drive 2 of which contain a dual rotating parity mechanism. for example with Parity P and Q
Stripe 1: Q 1 2 P
Stripe 2: 3 4 P Q
Stripe 3: 5 P Q 6
Stripe 4: P Q 7 8
The Q blocks are calculated using a Galois Field calculation. In total 2 drives can fail before the data loss with RAID 6.
- Volume Sets
These are where 2 or more drives or partitions are appended end-to-end to make a single volume. Commonly seen in older versions of Windows, all versions of Linux and some External hard disks (e.g. Lacie Big Disk series) and NAS boxes.
Recovering data from a failed raid array is a skilled job and can only be done by data recovery engineers that have an understanding of RAID Hardware, the Operating system and the file system used to store the data.
We have developed the software we use for raid recovery, and therefore our data recovery engineers are able to tweak the software parameters to suit the exact needs of your RAID controller to ensure the recovered data is intact.
Developing our own software enables us to maintain a RAID recovery rate of >96% and we only count those jobs where the critical data is recovered.
We are trusted as a preferred data recovery supplier for many international corporations, oil companies, computer manufacturers, software houses and many other large and small business sectors that demand a highly professional and reliable service.
Based in Cambridgeshire, we are within a short drive of Cambridge, London, Bedford, and Stevenage. We provide RAID recovery services throughout the UK, Europe and the Rest of the World
If you need to talk to someone about your RAID recovery requirements please phone 0800 072 3282 where you may talk directly to one of our engineers.