RAID 1 is one of the most widely used RAID setups due to its simplicity. But being so widespread means we see a lot of RAID 1 arrays in the data recovery lab.
RAID 1 is known as disk mirroring, so-called because your data is replicated across two or more disks. Because of this, your data is more secure with every drive you add to the array. RAID 1 is the perfect choice if you require high levels of performance coupled with data redundancy. In a RAID 1 array, two or more hard disk drives are combined to make an array with the capacity of one drive, and the read speed of multiple – along with at least one backup. When data gets written to a RAID 1 array, it gets copied to all the drives. Data can be read from the array incredibly fast due to the number of read/write heads that are in operation at the same time. But write speeds are slower, due to the need for the array to write data to all the disks in the drive.
What you lose in write speeds you gain in redundancy, which is the ability for the array to carry on working in the event of one of the hard drives failing. If you have a RAID 1 array with two hard drives, it has a 1-disk redundancy, and if you have a RAID array with three hard drives, it has a 2-disk redundancy. With a RAID 1 system, all of the drives in the array have to fail before you’ll need to a consult a RAID data recovery expert to recover your data.
Redundancy means that as long as one drive in the array is still in operation, your data is fine – although the faulty drive should be replaced as soon as possible. But one thing that many people don’t prepare for is the likelihood that all the drives in their RAID 1 array will fail at the same time. If you’re using the same model of hard drive purchased at the same time, there’s every reason to suggest they could fail at the same time. Hard drives have a limited lifespan, so one drive fails after five years of natural wear and tear, the chances are the other(s) could be on their way out. A RAID 1 system doesn’t protect your data against natural damage, such as a fire or flood, or a ransomware virus that could render your data lost. You also have nothing to stop human error, as any files deleted on one drive are deleted across the array. For this reason, we regularly see RAID 1 arrays in the lab for data recovery. In short – RAID 1 is not a substitute for a solid data backup!
