Correct Answer: A
Explanation/Reference:
Explanation:
RAID Level 1 is commonly called mirroring. It mirrors the data from one disk or set of disks by duplicating the data onto another disk or set of disks. This is often implemented by a one-for-one disk to disk ratio:
Each drive is mirrored to an equal drive partner that is continually being updated with current data. If one drive fails, the system automatically gets the data from the other drive. The main issue with this level of RAID is that the one-for-one ratio is very expensive - resulting in the highest cost per megabyte of data capacity. This level effectively doubles the amount of hard drives you need, therefore it is usually best for smaller capacity systems.
Incorrect Answers:
B: RAID Level 1 is not inexpensive, resulting in the lowest cost per megabyte of data capacity; it is the opposite.
C: RAID Level 1 is not unreliable resulting in a greater risk of losing data; it is the opposite.
D: RAID Level 1 is very reliable resulting in a lower risk of losing data. However, this is not an 'issue', it's a good thing.
References:
Krutz, Ronald L. and Russell Dean Vines, The CISSP Prep Guide: Mastering the CISSP and ISSEP Exams, 2nd Edition, Wiley Publishing, Indianapolis, 2004, p. 144
Krutz, Ronald L. and Russel Dean Vines, The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, New York, 2001, p. 90