OceanStor 9000 provides directory-level snapshots. What are the application restrictions of snapshots? (Multiple choice)

OceanStor 9000 provides directory-level snapshots. What are the application restrictions of snapshots? (Multiple choice)
A . If a directory or its subdirectories have snapshots, the directory cannot be destroyed
B . Remote synchronization of snapshot directories and the snapshot files in them is not supported
C . Snapshots do not support nesting. That is, snapshots cannot be created in the parent directory or subdirectory of a directory that has already created a snapshot.
D . Creating snapshots of the root directory is not supported

Answer: ABCD