When deciding to delete a data volume, however experienced a computer user or administrator you are, great care must be taken to double check that you are about to delete the correct partition or reinitialise the right disk. With any disk storage space the consequences can be quite serious, but for a RAID array the data tends to be even great importance to your company, without which their future may be put at risk.
Many RAID systems allow the possibility of replacing the drives with higher capacity one, rebuilding the array at each step. Once this has been done, it is tempting, rather than create another volume, but to extend the current one. While this process should work without error, it can in rare instances, especially as the result of an unfortunate power failure, lead to the volume becoming corrupt.
Should you make a mistake or suffer an unfortunately failure, it is important that you do not panic, as the act of deleting a partition, reinitialising a disk or extending a volume should not destroy any of the data, just render it inaccessible. Unless you know exactly what you are doing, the best option is to send the disk or RAID array for professional data recovery by a company such as DiskEng, who have the necessary expertise and knowledge to recover your data without putting it at risk.
Deleted Data Volume
Deleting the wrong volume is all too easy, especially if you’re distracted and fail to double check before confirming the action. The act of reinitialising a disk or deleting a partition will only clear the entries from the partition scheme data held at the start of the disk. If you then create a new volume which you format, it is only then that your data will start to be destroyed.
On some systems, when they are reinitialised the operating system may ask you about reformatting the disk. It is important to be sure before you confirm this action that it really was the correct disk that was reinitialised. Reformatting an HFS+ data volume will destroy almost all of the file system metadata, making it almost impossible to recover the data with its original names.
Some file systems may still be recoverable even a new volume has been formatted using the same space. XFS and NTFS provide the best chance of recovering most of the previously stored data. The extent of the possible recovery will be reduced depending upon the amount of data that has been written to the new volume before the mistake was noticed.
Partition Extension Failure
Rather than deleting a volume and recreating a new one to make use of further capacity follow an upgrade of the disks in a RAID volume is impractical. There are many utilities available which allow the partition or volume to be extended to make use of this space. These are usually very reliable, but an unfortunate loss of power or system crash at an inopportune moment could result in the volume becoming inaccessible. This could result in the volume becoming corrupt, usually due to a few metadata entries not being consistent, which may stop the volume being mounted by the operating system.
It is rare that it will result in serious corruption of the file system, but running utilities may put that data at risk. An attempt to automatically correct a volume with incorrect metadata may lead to corruption of the volume. The best solution is for a professional data recovery engineer to examine the data, who can decide which values are incorrect using their many years of experience.