Recently, in the global computer press has begun to appear quite a few articles on the topic "Why RAID-5 is bad” (here are some examples: one, two, and others).
We will try to explain why RAID-5 has worked so far, but now it suddenly stopped.
The capacity of hard drives has been growing without any specific tendency to a stoppage over the past few years. In addition, the capacity of the drives almost doubles every year, but their data transfer rate does not increase much over the same period. Yes, indeed, the drives get interfaces, such as SATA and SATA-II, and SATA-III is on its way, but there is a question “would these drives work faster?” or they just get new interfaces with the numbers of theoretical characteristics.
The usage of hard drives tells us that the capacity grows and the speed does not.