With RAID 1, data is mirrored across both drives. But what happens if both drives fail?
RAID, otherwise known as redundant array of independent disks, combines two or more hard drives into a single storage unit, offering various benefits depending on how it is set up. RAID 1 mirrors data across both drives in the array, so if one drive fails, your data is safely stored on the second. But both drives could - and very often do - fail.
RAID 1 is popular with home users because it's a basic RAID level that is easy to configure, and offers benefits like increased read speeds and redundancy, or a copy of the all data, offering protection against data loss. There are downsides, for example storage is limited to one drive in the array, and write speeds are unaffected, as data needs to be written to both drives. So if RAID 1 provides a complete, automatic backup of your data, why do our RAID recovery team work retrieving data from this type of array? The answer is that they see a lot of arrays where both drives have failed.
Two drives in a RAID 1 system failing at the same (or around) time can occur for a few reasons. Firstly, it's not uncommon for RAID 1 systems to be set up using two drives from the same batch. If they were both manufactured at the same time, they could also fail at the same time. Hard drives don't last forever, and generally last around five years. Secondly, an accident, such as a sudden drop or fall while the drives are in use, could physically damage both drives, rendering both of them operational. This is a common issue our RAID data recovery team see. Thirdly, while much less common, a natural disaster such as a fire or flood could also damage both drives in the RAID 1 system. RAID data recovery is possible if both drives are damaged, and the chances are that one of them will be fixable.
RAID 1 is not a substitute for a backup, and all critical data should be backed up regularly. If possible, the backup should be kept off-site. Additionally, keep an eye on the health of the hard drives in your RAID 1 system.