Most RAID arrays are used to store important data, often critical to the running of the company, so when it fails, it is important not to panic and potentially make the situation worse through an ill-fated attempt to recover the files. Such actions may result in the data recovery process becoming more complex or in the worst case lead to a total loss of data.
Any incident resulting in the failure of a storage device will be extremely stressful, especially when it involves a RAID array containing critically important data. It is important to think clearly and take the correct action, such as contacting a professional data recovery company who can give you advice and guidance about your failed RAID array. In the majority of cases where a RAID array has failed and gone offline, particularly as the result of a rebuild failure, the disks or RAID system should be send for professional data recovery.
Trust the Specialists Only
When a RAID array fails the first course of action is to call an engineer on-site to fix the problem. It is important to that they before they start any work which involves taking disks from the RAID array, or other actions, that they explain exactly what the problem is. If the engineer is unable to clearly explain the problem and the solution, it may be advisable not to allow them to continue and instead send all the drives for data recovery.
When any drive is removed from the array, its original location should be noted and the drive labelled clearly before proceeding. We have seen a number of cases where an original disk has been reintroduced into a raid, or placed in the wrong position, resulting in serious corruption of data on the array.
Never Reinitialise a RAID Array
Reinitialising a RAID array can be a time consuming process which may achieve nothing, but in some cases can result in the data becoming corrupt, such that the files are unrecoverable. If the RAID configuration is change, drives placed in a different order or even a different number used, the damage to the data can be severe.
In the worst case it can render all the data unrecoverable, although we have seen cases where following the failure of disk, it was removed and reinitialised with one drive less with the parity data recalculated. Fortunately, in this situation, using the data from these drives and original removed drive, we were able to recover all the client’s data, but the process is extremely complex and time consuming.
The Truth is Important
However, embarrassing you believe any actions you have taken which may have caused further damage to the RAID array, it is important that you tell our data recovery engineers everything. Without a full knowledge of the actions taken, data recovery can be like detective work, piecing together clues from data which is not in the correct position. It can potentially save a lot of time if we have all the facts, as the information can help our engineers determine how to overcome any issues.
Stop, Before Making the Problem Worse
The need to not attempt a quick fix which could result in all the data being lost, cannot be overstated, especially for a RAID containing data which is critical to your business. Seeking help when a failure occurs is not a sign of weakness, in fact demonstrating that you understand the importance of the situation, rather than rushing to seek a solution which might put the future of the company at risk.
Even if you believe you know the solution to the problem, attempting to explain it to someone else may reveal a problem with it, which could avoid a potential loss of data. At DiskEng we have many years of experience in dealing with RAID arrays of all types which have suffered many different types of failures. We have seen many examples arrive at our laboratory where attempts have been made to recover the data, which have severely complicated the process, some still fully recoverable ranging all the way to some where it has resulted in a complete loss of all data. Consult with the professionals at DiskEng before you make a mistake and lose data.