A. The read/write policy of eDevLUNs "write-back" applies to random access services, ensuring that data in the cache is cached as long as possible to improve the read hit ratio.

B. The read/write policy "Pairing" of eDevLUNs applies to sequential access services to release cache resources for other services as soon as possible.

C. The default read/write policy of eDevLUNs is applicable to common services to balance the hit ratio and disk access performance.

D. When the eDevLUN reads data, it reads the data to be read from the hard disk in advance based on the specified policy.