Lacie 4big Quadra White Paper - Page 1

RAID Technology White Paper As specialists in data storage, LaCie recognizes that almost all computer users will need a storage or backup solution and that people use and store data in different ways. Depending on their requirements, some people may prioritize performance and capacity, whereas others may be more interested in security and speed. In order to meet the storage needs of a wide range of users, LaCie's professional storage devices utilize RAID technology. RAID (Redundant Array of Independents Disks) is a simple technology that improves the performance of external storage solutions. RAID allows you to choose the best way to use your device to fit your needs. Simply put, RAID technology either divides or duplicates the task of one hard disk between many (or as few as two) disks to either improve performance or create data redundancy in case of a drive failure. You can decide how the device handles data by setting its RAID mode. This document describes the different RAID levels used in LaCie professional storage devices, and the characteristics used by each mode to optimize the speed, security or storage capacity of the hard drives in the RAID array. Important: No RAID configuration will protect data reliability from software or file system corruption. As a result, LaCie recommends that regular backups should always be performed to protect data. RAID Terms To better understand how RAID works, first familiarize yourself with the terms below: ✦✦ Striping is the splitting of data between multiple drives. Striped RAID arrays generally aim to merge maximum capacity into one single volume. ✦✦ Mirroring is the copying of data to more than one disk. Mirrored RAID arrays typically allow the failure of at least one disk in the array without any data loss, depending on the RAID level of the array. ✦✦ Fault Tolerance allows a RAID array to continue working (i.e. the data stored in the array is still available to the user) in the event of a disk failure. Not all mirrored RAID arrays are user friendly. For instance, some RAID devices must be shut down before a failed disk is replaced, whereas LaCie RAID devices feature "hot-swappaple" disk replacement that allows the device to remain on, and the data accessible, while the failed disk is replaced.