What Is the Correct Description of the Huawei Oceanstor 9000

What is the correct description of the Huawei Oceanstor 9000 read and write process?

A) The CA is responsible for initiating the metadata query
B) If the global cache read hit, read from the global cache without having to go to the OBS to read the stripe data
C) Reading data, the MDS is responsible for assembling the slitting data
D) When writing data, calculate the redundant data by MDS