A RAID set is created from eight disks, and a RAID level 5 is implemented on the
ID: 3869423 • Letter: A
Question
A RAID set is created from eight disks, and a RAID level 5 is implemented on the RAID set. If the size is 32 KB, what is the stripe size? 128 160 224 256 A system has three components, and all three components need to be operational from 8 AM to 5 PM: Monday to Friday. During a particular week, failure of component 3 occurred as follows: Monday = 7 AM to 11 AM Tuesday = No failure Wednesday = 4 PM to 7 PM Thursday = No failure Friday = 12 PM to 2 PM Saturday = 5 AM to 8 AM Sunday = 6 PM to 9 PM What is the availability of component 3 for this week?Explanation / Answer
1. with RAID5 you have to exclude one block for parity, so it would be a 224k stripe (7x32k).
So right option is c) 224
2. availability = system uptime / ( systrm uptime+ system downtime)
system downtime = 3 hrs on Monday + 1 hr on Wednesday+ 2 hrs on friday = 6 hrs ..
total operational time = 9*5=45 hrs
total uptime = 45-6 = 39 hrs
availablity = 39/(39+6) = 0.86 ... so availability percentage is 86%