Question Details

(Solution) - One can uncover the pattern size with the following code

Brief item decscription

Solution download

Item details:

One can uncover the pattern size with the following code. The code accesses the raw device to avoid file system optimizations. The key to all of the Shear algorithms is to use random requests to avoid triggering any of the prefetch or caching mechanisms within the RAID or within individual disks. The basic idea of this code sequence is to access N random blocks at a fixed interval p within the RAID array and to measure the completion time of each interval.

One can uncover the pattern size with the following code.
If you run this code on a RAID array and plot the measured time for the N requests as a function of p, then you will see that the time is highest when all N
One can uncover the pattern size with the following code.
Figure 6.26 Results from running the pattern size algorithm of Shear on a mock storage system.
Requests fall on the same disk; thus, the value of p with the highest time corresponds to the pattern size of the RAID.
a. Figure 6.26 shows the results of running the pattern size algorithm on an unknown RAID system.
? What is the pattern size of this storage system?
? What do the measured times of 0.4, 0.8, and 1.6 seconds correspond to in this storage system?
? If this is a RAID 0 array, then how many disks are present?
? If this is a RAID 0 array, then what is the chunk size?
b. Draw the graph that would result from running this Shear code on a storage system with the following characteristics:
? Number of requests: N = 1000
? Time for a random read on disk: 5 ms
? RAID level: RAID 0
? Number of disks: 4
? Chunk size: 8 KB


About this question:

This question was answered on: Jul 11, 2017

PRICE: $15 (18.37 KB)

Buy this answer for only: $15

Pay using PayPal (No PayPal account Required) or your credit card. All your purchases are securely protected by PayPal.

Need a similar solution fast, written anew from scratch? Place your own custom order

We have top-notch tutors who can help you with your essay at a reasonable cost and then you can simply use that essay as a template to build your own arguments. This we believe is a better way of understanding a problem and makes use of the efficiency of time of the student. New solution orders are original solutions and precise to your writing instruction requirements. Place a New Order using the button below.

Order Now