Deduplication is a technique that eliminates redundant copies of data from a storage device, such as a SAN disk drive. Deduplication can reduce the amount of storage space required andimprove the performance and efficiency of the storage system. Deduplication works by identifying and removing duplicate blocks of data within or across files, and replacing them with pointers to a single copy of the data. Deduplication can be performed at the file level or the block level, depending on the granularity and the algorithm used. Deduplication is often used in backup and archive scenarios, where data is highly redundant and can be deduplicated across multiple backups. Deduplication can also be used in primary storage scenarios, such as SAN disk drives, especially for all-flash arrays that implement deduplication techniques. Deduplication is different from compression, which is another technique that reduces the size of data by removing redundant information within a data block. Deduplication and compression can work together to achieve higher storage savings. Deduplication is also different from encryption, which is a technique that protects the confidentiality and integrity of data by transforming it into an unreadable form using a secret key. Deduplication is not effective for encrypted data, as encryption makes the data appear random and unique. Deduplication is also different from sanitization, which is a technique that permanently erases data from a storage device, making it unrecoverable. Deduplication does not erase data, but rather consolidates it and removes duplicates. Therefore, the correct term for eliminating redundant copies of data from a SAN disk drive is deduplication. References: Using Deduplication and Compression, Understanding Data Deduplication, 7.6 Using Deduplication techniques in SAN infrastrucutre.