Postgre Question:

RAID serves for two data storage requirements
1]Reliability
2]Performance
->Reliability-It maintains multiple copies of same data in
array of disks to make the storage fault tolerant in case of
disk failure.
->Performance-Different bits of a data component is stored
across an array of disks(bit striping) so that access time
is greatly reduced since single read time is enough to read
all the bits since they are in different disks, thus
boosting the performance.