technically known as "reconstruct write" - a new method for updating parity
JonP gave a short description of what "reconstruct write" is, but I thought I would give a little more detail, what it is, how it compares with the traditional method, and the ramifications of using it.
First, where is the setting? Go to Settings -> Disk Settings, and look for Tunable (md_write_method). The 3 options are read/modify/write (the way we've always done it), reconstruct write (