A database administrator would like to start encrypting database exports stored on the SAN, but the storage administrator warns that this may drastically increase
the amount of disk space used by the exports. Which of the following explains the reason for the increase in disk space usage?

A.
Deduplication is not compatible with encryption

B.
The exports are being stored on smaller SAS drives

C.
Encrypted files are much larger than unencrypted files

D.
The SAN already uses encryption at rest

Explanation:
Encryption adds overhead to the data which results in and increase in file size. This overhead is attached to each file and could include the encryption/decryption
key, data recovery files and data decryption field in file header. As a result, requires increased storage space.
Incorrect Answers:
A: Data deduplication is a specialized data compression technique for identifying and eliminating duplicate copies of data. Modern cryptography often includes
compression deduplication though some do not.
B: A storage area network (SAN) is a secondary network that offers storage isolation by consolidating storage devices such as hard drives, drive arrays, optical
jukeboxes, and tape libraries. The size of the storage device is irrelevant as it is part of the SAN.
D: If the data is already encrypted it would not lead to an increase in storage space.

http://en.wikipedia.org/wiki/Data_deduplication
https://technet.microsoft.com/en-us/magazine/2006.05.howitworks.aspx Stewart, James Michael, CompTIA Security+ Review Guide, Sybex, Indianapolis, 2014, pp
251-