Often called a mirroring, RAID 1 uses a pair of hard disk drives onto which the same data is written, maintaining a mirrored copy of the data. Although this configuration does limit the capacity of the RAID to the size of a single hard disk, it does come with the benefit of 100% data redundancy. This type of RAID has become increasingly popular, particularly for storing the operating system. It is most commonly utilised with the server environment, although its use has become more widespread, including consumers and data storage drives when data security is preferred.
This 100% redundancy does not however guarantee that the RAID won’t failure, so it is important that a backup strategy is put in place. It is also important, that when a hard disk drive in a RAID 1 array suffers a failure, that it is immediately replaced, with the data re-mirrored to the new drive, in order to avoid a failure or potential data loss.
When a RAID 1 array is setup, it is quite common for the two hard disks to have been bought from the same source, which then operate within the same environment. Over time hard disks will slowly develop more unreadable bad sectors, which the drive automatically maps out for spare sectors as they are encountered. This spare sector area of the disk is however only a finite space, meaning that once it is full, any new bad sectors will be presented to the operating system, at which point a failure of the drive will be reported.
Hard disk drives of the same model operating in the same environment are quite likely to develop these bad sectors at a similar rate, meaning that once one drive has started to fail, the second drive in the RAID 1 array may be about to fail. If this drive suffers a failure while the array is being re-mirrored, the RAID 1 array will fail and likely go offline.
The number of RAID 1 arrays in use has increased, leading to an increase in data recovery requirements. If your RAID 1 array fails, it is essential not to panic and attempt to make any rash decisions which may endanger the integrity of your data. Although this type of array in theory provides two chances at recovering your data, it is essential not to take any risks when a problem occurs, particularly when it is the result of a physical drive failure. When your RAID 1 array fails, you power it down and send the disks, along with any other drives onto which any a rebuild was attempted.
When sending your RAID 1 array for data recovery, you should indicate which was the first drive to fail and if included to which drive the rebuild was attempted. This is essential information, as it is not always easy to determine which drive failed first without undertaking a detailed low level scan of the data.
When a RAID 1 array arrives at our laboratory for data recovery, it is essential to overcome any physical drive issues and secure sector-by-sector images of the drives. These drives then be processed to recover your data.
We have vast experience in recovering data RAID 1 mirrored configurations, no matter what the failure, from physical drive failures, through to user errors, such as deleting or reformatting for a partition.