In the Scenario of Protecting the Database, the Slave Uses

In the scenario of protecting the database, the slave uses the virtual snapshot method to verify the services of the production end and the DR-side and discover the data of the DR on the disaster recovery end. What are the possible reasons that the library can not start normally? (Multiple choice.)

A) After a snapshot of the LUN of the redundancy site is created, the snapshot is not activated at the same time.
B) Disaster recovery side of the data stored in the cache, not yet written to the hard disk.
C) When creating a snapshot on the disaster recovery end LUN, the production end is copying data to the disaster recovery end.
D) The production end and disaster recovery end adopt the disaster recovery solution of incremental LUN copy, and the incremental data link is abnormal during the synchronization.