Definition: RAID 1 | Mirroring

RAID Level 1

RAID Level 1 – (2 Drive Minimum – Data Redundancy) Mirroring:  In its simplest form RAID 1 simply duplicates data onto two different hard drives simultaneously, thereby providing data redundancy.  Data redundancy means that if either of the two hard drives fails for any reason no data will be lost as there is an exact duplicate or ‘mirrored set’ of the data on the other drive.  Data integrity is maintained as long as either of the two hard drives in the array is functioning.  In the event that one of the drives does fail it is simply swapped out for a new working drive.  The ‘array’ then ‘rebuilds’ itself by duplicating all of the data onto the new drive and recreating the ‘mirrored set’.  Data is, however, vulnerable while a rebuild is in progress.