Deleting or losing the configuration of your RAID can result in panic, at a time when clear thought is essential, to avoid making a bad decision which could put the data stored on the array at risk. Although there is software available which purports to be able to determine the configuration of a RAID automatically, it not a simple process, as it usually takes experience combined with an in-depth knowledge or RAID configurations and the underlying file system, a task best performed by a RAID data recovery specialist.
Hardware failure, logical data corruption of the configuration or accidental deletion are just some of the methods which can cause your RAID to fail. Your first action in all cases of RAID array configuration loss is to contact a professional data recovery company, with years of experience in recovering data from RAID systems, who will guide you through the process and how best to send hard disk drives in order to recover the files.
Failure of the Hardware
For a RAID contained in a cabinet or purpose built case it is quite common for the configuration to be stored on a ROM chip on the controller board, normally accessed when the RAID array is powered up. Should the controller board fail, it will need to be replaced, which means the RAID configuration will be lost. You should not make any attempt at reconfiguring the RAID array after the controller board has been replaced as a mistake could corrupt the data held on the drives.
Logical Data Corruption
Most dedicated SAN RAID arrays will use a Logical Volume Manager (LVM) which stores the configuration on the drives, so that it is picked up at boot time. Software RAID arrays will usually store the configuration in a file or also use an LVM. This approach works well as long as the LVM does not become corruption, such as a bad sector on the disk or malicious damage through malware. Should this happen the RAID array will be loaded and remain offline.
RAID Configuration Deletion
Although malicious action is possible, most deleted RAID configuration occurs through operator, usually as a result of rushing through the steps required when reconfiguring systems which have multiple RAID arrays attached to them. The result problem arising from this is exactly the same a hardware fault or logical corruption, in that the data is inaccessible.
Reconfiguring the Array is Not an Option
Never attempt to reconfigure the RAID array, even if information has been left detailing how it was meant to be originally set up. It is not uncommon for the configuration of a RAID array to differ from the details an engineer has left about how it was originally set-up. This is usually an oversight, but some unscrupulous engineers have claimed to set up a RAID with redundancy, but cut costs by only using a box capable of striped or mirrored arrays.
Even if the configuration is correct, there is only a slim chance of success, whereas an incorrect configuration could make data recovery a much more complex process, or in the worst case result in some or even all of the data becoming unrecoverable.
RAID Array Data Recovery
The first action undertaken by our data recovery specialist will be to inspect the drives for any issues, which need to be fixed, before sector-by-sector image copies of each drive in the array are secured to one of our servers. From the images of the drive our RAID data recovery specialists will determine the configuration of the RAID. Our success rate in recovering data from a RAID which has suffered a lost configuration is high, with partial recoveries or failures occurring as a result of attempts to reconfigure the RAID before being sent for recovery.
