The customer's existing network database business runs on an OceanStor V3 storage, and the database uses 6 LUNs in total.
Now it is necessary to migrate the data on the storage to OceanStor 18000, and use the array-side function to complete the data migration. Which of the following statements are correct? (Multiple Choice)

• A. Data migration is implemented through LUN copy. During the copying process, the migration rate can be dynamically changed.
• B. When multiple LUNs of a customer's business use remote replication to implement data migration, multiple remote replication tasks need to be added to a consistency group.
• C. Online data migration can be completed using the remote replication function.
• D. After the LUN copy or remote copy migration is completed, the service can be started without any configuration on the host.

When migrating an NFS share, if the target side has set the root permission to compress root_squash on the shared directory, using the migration server migration will cause the Unix Node permission to not be accurately migrated to the target side.

• A. FALSE
• B. TRUE

A user purchased a set of Huawei OceanStor 9000 products for video surveillance services. Which of the following description is correct? (Multiple Choice)

• A. In order to improve the high reliability of the visual data storage device, the user has enabled the SecureVidec feature. If the data disk adopts the 4+1 protection level and 2 copies of data are damaged, for the read operation, the system only successfully reads 3 copies and returns 3. The 2 copies of the data that are successfully read and the 2 copies that fail to be read will be filled with 0 and returned.
• B. If the user enables the SecureVideo feature, if the data disk adopts the 4+1 protection level, 2 copies of the data are damaged. For the write operation, only 3 copies will return a successful write response, and the 2 copies of the write failure will be complemented by 0, and the write will be processed successfully.
• C. After the user enables the SecureVideo feature, the files with incomplete data in the system will be cleaned up during data consistency scan.
• D. After the user enables the SecureVideo feature, the file corruption event has been reported and recorded when the file is read/written. No longer report data recovery failure alarms

After the hybrid all-flash array is upgraded, in which of the following situations? you cannot try to downgrade the system in order to solve the problem.

• A. The business cannot be recovered after the upgrade is completed
• B. Data is lost after the upgrade is complete
• C. Configuration data is lost and cannot be recovered after the upgrade is complete
• D. System performance drops after the upgrade is complete