As hard drives provide a pivotal role in a PC it is essential that they run correctly and at high performance. Hard drives do not last forever and can develop errors over time. Also, when compared to main memory, they can cause some serious performance problems. One such problem, known as threshing, can cause huge performance problems.
Raid 0 Striped – This
provides improved performance and additional storage. However it does
not provide any fault tolerance so any errors on the disks will
destroy the raid.
Raid 1 Mirrored –
Each disk provides the same information and provides extra fault
tolerance. Due to the mirrored information this increases read access
time. However as data has to be written to two hard drives which
causes a slight delay in saves.
Raid 3 – 4 Striped parity – This requires 3 disks in order to be in the array. As well as fault tolerance it provides parity checks and error correction codes. The parity is stored on a single drive which causes a system bottleneck. This helps drives to continue working even when one of the drive fails. The lost data can be calculated using the parity data stored on the parity drive.
