When a RAID failure occurs, it is important not to undertake any actions which may make the situation worse, possibly leading to a total loss of data. In many cases of a RAID failure, what might have been a fairly simple data recovery has been made extremely complex or even in the worst case impossible, due to inadvisable attempts to repair the problem.
The failure of a storage device is very stressful particular for a RAID system, which are often used to store the company’s most valuable data files. Under stress we often struggle to think clearly, so it is important to talk to a professional RAID data recovery company who can guide you through the best approach. In many cases the only viable solution is to send the RAID array for data recovery, particularly if a rebuild has failed, or the RAID has gone offline.
Trust Only Professional Engineers
If an engineer called on-site is unable to adequately explain in clear language what the problem is, and their intended solution they may be about to take an unnecessary risk with your data. An engineer with experience should also explain that for a failed RAID array, data recovery is quite likely to be the best solution to the problem.
Any replacement drives or those removed from the array should always be labelled clearly, to denote which drive bay they occupy. It has been known for an engineer to attempt a rebuild and when deciding to place the original drive back into the array, has swapped another.
Never Reinitialise the RAID Array
In the best case reinitialising a RAID array will achieve nothing other than taking time. We have seen the consequences of a RAID array being reinitialised, which has in some cases rendered all data unrecoverable. In others we have been required to create some extremely complex virtual RAID arrays to overcome the problems caused, in one particular case a RAID 5 being reinitialised with one less drive than the original array configuration.
When a RAID array is reinitialised it will need to ensure that any parity information contained on the drive is resynchronised. It is easy to understand how with a different number of drives, or other important configuration change, or even the wrong drive order, that the data can become seriously corrupted by the process.
Tell Us the Truth
Always tell us the ever process that was undertaken before the RAID array was sent for recovery. Feigning ignorance can cause the data recovery process to take a lot longer than normal, as it becomes a matter of detective work to determine what is wrong with the RAID array. Often this is due to not wanting the boss to know what happened, but for the purposes of data recovery it could be critical, especially if the timescale for recovering the data is short.
Always Stop, Think and Ask For Help
It is easy to panic and quickly attempt to fix the problem using the solution you discover, which may not be appropriate for your situation. It is best to stop and think over what has happened and then ask for help. Asking for help is not a sign of weakness, or lack of understanding, as it may save you making a mistake which could put the continuity of your company at risk. Even if you believe you know the solution, try to explain it to someone else, as that may reveal any potential issues that could lead to an unnecessary loss of data. At DiskEng we believe the best solution following the failure of a RAID array to power it down and call us to discuss the problem with a professional RAID data recovery specialist.