123. Which of the factors need not be taken into consideration while choosing a RAID level? a. Monetary cost b. I/O requirements c. Performance when the disk has failed

alagram. Question 2 Answer the following questlons. (250 words max/question) 1. What are the main goals of RAID technology? How does it achleve them? 2. How does disk mirroring improve reliability? 3. What techniques are used to improve the performance of disks in RAID? 4. Suppose you use RAID level 0+1 (striping and mirroring) to do blockwise striping over 4 disks, and you have mirrored the data on another 4 disks. Under optimal circumstances (i.e., equal distribution of requests, perfect load balancing), the number of block read accesses allowed by the RAID system would be Explain your answer. a. the same as for a single disk b. two times higher than a single disk c. four times higher than a single disk d. eight times higher than a single disk Page 2 / 2

Why do differing systems place disk directories in different track locations on the disk? What are the advantages of using each location? (Described putting directory at inner, middle, and outer tracks, with description of advantages for each location)

1. Given that in a RAID 2 there are 30 disks in total, what is the space efficiency of the RAID 2?  Given that in a RAID 2 there are 25 disks in total, what are the possible space efficiencies of RAID 50?