About OceanStor V3 file deduplication compression characteristics, which of the following statement is correct? (Multiple choice)

About OceanStor V3 file deduplication compression characteristics, which of the following statement is correct? (Multiple choice)
A . can only be opened when creating the file object, during the execution of the business can’t be turned on or off data deduplication compression.
B . with the method of online processing, deduplication compression before the data is written to disk.
C . When open the deduplication and compression simultaneously, the data will first be deduplication and then carry out compression.
D . use SmartCache can accelerate deduplication fingerprint lookup performance.

Answer: BCD