With 2.4.0, software RAID in Linux will come of age. The functionality that previously was only available through separate patch sets will finally be part of a "Stable" kernel release. However for much (hopefully not all) of the 2.4.0-test series, raid5 performance was extremely poor. This talk will look at how differenced between 2.2 and 2.4 affected software RAID, and how the various issues were (finally) dealt with. In particular, it will look at raid5 performance and what was slowing things down.