How to Recover Lost Data from RAID 6?
Data is everywhere, from financial markets to user behavior patterns. With data being foremost for any individual or organization, keeping it secure from unexpected loss is important, as losing critical or confidential data could result in huge financial losses. Therefore, securing your data at multiple levels is the need of the hour. To ensure the same, various levels of Redundant Array of Independent Disk (RAID) are used. RAID 6 is just another type of RAID level that offers enhanced security against data loss and increased data availability.
Before we proceed with RAID 6 data recovery, let’s see a brief overview of RAID 6 and its working.
How Does RAID 6 Work?
RAID 6 uses a striped block configuration for storing data and its parity in different blocks. Each block contains a portion of the data in the active drives and parity in the backup drives. The setup also has multiple reserve drives, which are not used in regular functioning and storage. These are kept empty and are used when a drive fails. RAID 6 has a fault tolerance of 2 and requires at least 4 data drives for the whole setup so that if a case arises where two drives fail, the data can be recovered using the other 2 drives .
Though the performance of RAID 6 is mediocre due to its complex checksum algorithms and the parity data written twice, its disk failure tolerance makes it a reliable option. RAID 6 works on the Reed-Solomon parity model, which is known for correcting data errors automatically. If a portion of data stored on the active drives gets damaged or lost, the array controller recalculates and recovers it automatically from parity. However, if three or more drives fail due to controller failure, virus attack, server crash, hardware
issue, etc. then the RAID setup fails and the data can only be recovered using a third-party RAID recovery software.
The RAID 6 array remains functional when one or two active drives fail and the disk array status changes to Degraded. In such a case, the failed drives could be swapped with a hot spare disk as soon as possible to rebuild the lost data.
Reasons Behind Data Loss in RAID 6
RAID 6 is known for its reliability and data security. However, just like any other storage device, RAID too is vulnerable to data loss due to numerous reasons like human error, physical/logical damage, software failure, etc.
A RAID 6 configuration could fail due to –
· Hard disk corruption
· Absence of RAID partitions
· Server crash
· Unexpected power loss
· Raid controller not responding
· Disk read error or URE error
· DDoS Attack
How to Recover Lost Data from RAID 6?
When we talk about RAID data recovery, there are 2 cases of data loss in the RAID 6 configuration. First is Single-Disk or Dual-Disk failure and the second is Three or more disk failure. In the former case, the data can be recovered by swapping the damaged drives with the newer ones and then rebuilding the data. However, the latter case leads to a complete RAID failure and the drive data becomes inaccessible. In such a case, professional RAID recovery software could lend a helping hand in recovering lost files and data from a failed RAID.
Case 1: Single-Disk or Dual-Disk Failure –
This is a case where you can swap a hot spare disk with the degraded one so that the controller can rebuild the lost data. Once you replace the failed drives, the controller will initiate the rebuild process.
Case 2: Complete RAID 6 Failure –
This is the latter case where three or more disks fail, leading to complete RAID array failure. In this case, a professional RAID recovery software like Stellar Data Recovery Technician could be useful. It can easily recover lost data from logically corrupt, failed, and crashed RAID arrays.
The software performs the RAID 6 data recovery in a streamlined manner by first rebuilding the RAID 6 and then scanning the volumes for the lost data. Here are the detailed steps which you can follow to recover your lost data back from a failed RAID array:
· Download and Install Stellar Data Recovery Technician from the official website.
· Launch it.
· On its Home Screen, check the type of data you want to recover. By default, All Data is checked. Click on Next once you’ve finalized your choice.
· On the next screen, check the ‘RAID Recovery’ option at the bottom and click Scan.
· A new ‘RAID Reconstruction’ window will open. Follow the steps in the given order:
· Go to the RAID 6 tab.
· In the ‘Select Hard Drives to Reconstruct RAID’ section, select the missing Hard drives and click on ‘>’ to add them under the ‘Move hard drives up/down for disk order’ section. You can remove any hard drive at this stage by clicking on the ‘<’ key.
· In the ‘Move hard drives up/down for disk order’ section, place the drives in order by using the UP and DOWN buttons present there.
· Below this, in the ‘Select RAID Parameters’ section, select the details for various parameters using their respective drop-down menus.
· Note — If you don’t know the Parameters, you can check the ‘Don’t know start sector of drives. Show list of probable start sectors’ checkbox. Under it, select a value for ‘Select one or more probable start sectors’ using the drop-down menu.
· Click on Build RAID. The software will start building the RAID, and a single RAID volume will be displayed next on the ‘Selected Constructed RAID’ screen.
· On this screen, the reconstructed RAID will be shown as a single volume. Select it and click on the ‘Show Volume List’ button to list all the found volumes under it.
· Select the RAID volume from where you wish to recover your lost data and click on Scan.
Note — If the volume is not in the list, you can select the ‘Physical Disk’ and click on Scan to search for lost volumes. You can also perform Raw Recovery in this case. If you are not satisfied with the displayed RAID 6 build, you can click on Reconstruct RAID to restart the RAID rebuilding process.
· Once the Scanning process is complete, it will list all the recovered files. You can preview the required files and then click the Recover button to save them at the desired location.
Note — If you can’t see the required files after performing Quick Scan, you can also perform Deep Scan by clicking on the ‘Click Here’ button in the Preview window.
Conclusion
RAID 6 configuration is a great way of storing and securing large volumes of data in a single place. While RAID 6 offers great reliability, it is still susceptible to data loss for various reasons like disk failure, controller failure, malware attack, etc. However, RAID 6 data recovery can be easily carried out with a professional RAID recovery software like Stellar Data Recovery Technician. We hope this article helped you understand the RAID 6 configuration and ways to recover data in case of RAID failure.