Operating Systems

I/O Performance Analysis

Part 1

Start your Linux Partition from a fresh boot and open the Terminal. Do not open any other applications at this time.

NOTE: You may need to install the “sysstat” and “iotop” package for this exercise:

Type command:

apt-get install sysstat

apt-get install iotop

run the following command to create a 50MB test file

dd if=/dev/zero of=test.file bs=1024 count=50000

Now run this command to repeatedly create another file from the first file. This is creating I/O load on the system.

while true; do dd if=/test.file of=test2.file bs=1024;rm test2.file; done

Using iostat watch the I/O for your devices and all of its partitions over 30 second intervals. List the command used and record your findings. Do not display CPU statistics.

Using iotop, report which three processes are the most I/O intensive.

Part 2

Add 3 new 50 MB Fixed Size Virtual Disks to your linux Partition. This is done using the Virtual Box interface while your Linux Virtual Machine is shut down.

Switch to the root user

sudo su –

Using fdisk create 3 new “linux raid auto” partitions. One for each new drive added. Use the full space available on each disk.

i.e. /dev/sdb1 /dev/sdc1 /dev/sdd1

install “mdadm” package

apt-get install mdadm

*If asked for a “mail server” choose “No Configuration”

**This can take a few minutes to install.

Create a striped array (RAID 0) using all three disks.

Create Filesystem on New Raid 0 Array

Mount your new striped filesystem

What is the size of the filesystem? Why?

Repeat Part 1 of this assignment but this time make sure you are using your new striped filesystem. To do that just change to that directory

cd /stripefs

Summarize your findings about your new RAID 0 filesystem and iostat output.

Did you achieve desired results? If not, why not and what would need to be changed in a real world production server to achieve desired results?

Submission Requirements

You will submit a Word or Libre Writer Document which contains results from the above analysis and responses. I do not have access to your system so you need to be sure to provide screenshots for anything I cannot possibly know.

I don’t need screenshots for every piece of output you analyze during this assignment. Just give screenshots which show snapshot information to support your overall findings.

Please insert your screenshots into your word document with supporting documentation which meets all requirements. You will be penalized for any results which are not backed by proof.