162If disk drives of different capacities are used, there will also be unusedcapacity on the larger drives.Because RAID 0 does not offer Fault Tolerance, meaning that you cannotrecover your data after a disk drive failure, we do not recommend a RAID 0Volume for your unit.RAID 0 Volumes on this unit consist of one or more disk drives.RAID 1 – MirrorWhen a RAID Volume is mirrored, identical data is written to a pair of diskdrives, while reads are performed in parallel. The reads are performed usingelevator seek and load balancing techniques where the workload is distributedin the most efficient manner. Whichever drive is not busy and is positionedcloser to the data will be accessed first.With RAID 1, if one disk drive fails or has errors, the other mirrored disk drivecontinues to function. This is called Fault Tolerance. Moreover, if a spare diskdrive is present, the spare drive will be used as the replacement drive and datawill begin to be mirrored to it from the remaining good drive.The RAID Volume’s data capacity equals the smaller disk drive. For example,a 100 GB disk drive and a 120 GB disk drive have a combined capacity of 100GB in a mirrored RAID Volume.If disk drives of different capacities are used, there will also be unusedcapacity on the larger drive.
