"The storage capacity and data retrieval speeds of Hard Disks
have increased multiple folds in last few years. However for large
business organizations, which not only need to store terabytes of
invaluable data but access them frequently as well. These
organizations cannot afford to let their systems go offline even
for a short duration of time. Moreover they cannot even think of
loosing even small amount of data due to disk failure or for that
matter any other reason.
"A single hard disk cannot fulfill all these requirements no
matter how large is the storage capacity or how good the
performance and quality of disk is. The need here arises of a
system that can store large volumes of data, provides fault
tolerance, scalable in terms of increasing storage capacity and
above all that can be reliable..."