RAID 5 Array Recovery

A minimum of 3 disks is required for a complete RAID 5 array. A RAID 5 can be implemented by a software or hardware controller. In most scenarios, a hardware controller is used. The cost of RAID hardware controllers has dropped significantly in recent years. The performance benefits of a hardware controller over a software controller are significant.

RAID 5 controllers distribute data so that a ‘parity’ block of data is created on the disk set. If one disk fails the parity data block can be used to substitute the data from the missing disk. The diagram below shows the method in which data is stored in a RAID 5 array.

RAID 5 Diagram

Overall capacity of a RAID 5

Only one disk worth of parity data is stored. This means the total storage space is the equivalent to the total number of disks multiplied by the capacity, minus the capacity of one disk i.e. N – 1 x (capacity). The largest RAID 5 which CDR recovered data from was in 2016. It contained over 90TB of data spread through 24 HDDs. We most frequently receive in RAID 5 arrays which have between 4 and 6 member disks.

Reasons for RAID 5 failure

Multiple disk failure is the primary reason for RAID 5 failure. Common failures in HDDs include bad sectors or failure of the read-write heads. Failures in SSDs are due to Flash NAND degradation or firmware faults.

Secondly, RAID 5 arrays can fail due to a fault on the RAID controller, or loss of the configuration data stored within it. When a RAID controller fails it is possible that all the disks within the RAID still have normal functionality. In these cases do not attempt to “re-initialise” or re-create the RAID configuration in the controller. This can lead to the disks being formatted and can result in unrecoverable data loss.

Business critical data

Do not leave the recovery of your critical data to chance. Cheadle DATA Recovery Ltd has provided professional data recovery services for a number of years. CDR was established in 2006 and offers reliable and effective data recovery of RAID arrays.  We have many satisfied customers after the full recovery of data from their failed devices. If your data is critical do not attempt to recover the RAID array yourself; frequently this can lead to a ‘bad-rebuild’ and unrecoverable data loss.

Please contact Cheadle DATA Recovery Ltd for advice on 0161 408 4857. We do not make any charges for diagnosis of the array. CDR can provide a second opinion on RAID recovery when other data recovery companies have failed. We specialise in the recovery of non-standard controllers (including X-Serve, HP Delayed Parity), and EMC Fujitsu base disks using 520+ bytes-per-sector.

We will always provide you with a fixed price quotation in advance of receiving your failed RAID array.

What services can CDR provide?

  • Recover your lost data.
  • Provide a disk image to allow an attempt to make the computer/server bootable.
  • Advise on appropriate backup method.
  • Provide a fixed price quotation in advance of receipt of any RAID array.
  • Experienced staff with technical expertise can talk you through the process, including any early stage diagnosis before the RAID is received.
  • Please phone 0161 408 4857 to discuss your data recovery.