A. It improves resync operations when the disk comes online after being taken offline for maintenance purposes.
B. It improves performance in the extended cluster configuration by reading from a local copy of an extent.
C. Fewer extent pointers are needed to describe the file and less memory is required to manage the extent maps in the shared pool.
D. This feature enables faster file opens because of the reduction in the amount of memory that is required to store file extents.
答案：（C、D）