It used to be that RAID was only available in expensive server systems. However, with the advent of inexpensive RAID controllers, it seems it has pretty much reached the mainstream market. Performance nuts, such as myself, are always looking for the latest technology to give us that edge we need. Of course, the mainstream implementation has it´s limitations, and RAID isn´t really for everyone. There are many levels of RAID being used today. Before I go into the different levels, I´d like to discuss the basic concepts behind these levels in a little more detail.