RAID 0, RAID 1, and Redundancy

A Redundant Array of Independent Disks – commonly referred to as RAID – combines two or more hard drives into a single unit.

RAID in its most basic form is known as disk striping, or RAID 0. Here. Data is striped across two or more hard drives, offering increased storage space. Additionally, because there are multiple sets of read/write heads working in tandem, read/write speeds are faster. However, RAID 0 provides the user with no fault tolerance or redundancy, and because data is striped across both or all drives in the array, if one drive fails, the result is total data loss. For this reason, RAID 0 is not a suitable solution for users who are storing important data. Each drive that you add to your RAID 0 array increases the likelihood of failure; for this reason, users with more than two hard drives generally opt for a different RAID configuration.

RAID 1, or disk mirroring, replicates your data across all hard drives in the array, meaning if one drive fails, you still have copies on the remaining drives. The downside is that you only have the storage capacity of a single drive, since data is mirrored across the rest. Read speeds are faster, due to multiple sets of heads in operation, but write speeds are slower, since data needs to be mirrored to all drives in the array. However, what you lose in write speed and storage capacity, you gain in redundancy. With RAID 1, all drives in the array would have to fail before you would need to consult a RAID recovery specialist. For this reason, RAID 1 would be a good storage solution for home users who don’t particularly require masses of storage space, but do require adequate protection against data loss.

So what do we mean by “redundancy”? Simply put, it refers to storing the same data in multiple locations. In the context of RAID 1, as long as one drive in the array is still in operation, your data will be fine, although the faulty disk should be replaced as soon as possible. However, RAID 1 is not a substitute for a backup; it doesn’t protect your data from human error, natural disaster like fires or floods, or the possibility of all the drives in the array failing simultaneously.

RAID Recovery