Editing Futotemporarywikipage (section)

==== 5.3 Testing the setup - software run first. ====

Let’s simulate a fault condition on <code>/dev/md126</code> which is what I set up as the RAID1 array for the operating system installation; this is where we created the logical volume for <code>/</code>

# Check the status of it as it is now:

<pre>sudo mdadm --detail /dev/md126</pre>
<ol start="2" style="list-style-type: decimal;">
<li>If it shows up as healthy, run the script to make sure we do not have false positives.</li></ol>

<pre>sudo -u root /root/mdadm_alert.sh</pre>
<ol start="3" style="list-style-type: decimal;">
<li>If no false positives, simulate fault condition:</li></ol>

<pre>sudo mdadm /dev/md126 --fail /dev/sdb3</pre>
<code>/dev/sdb3</code> was the drive &amp; partition that was used in my RAID array. Yours may differ, refer to the output of <code>mdadm --detail</code> to see how your RAID array is comprised, and then fail one of the two devices.

<ol start="4" style="list-style-type: decimal;">
<li>Run the monitoring script to test again.</li></ol>

<pre>sudo -u root /root/mdadm_alert.sh</pre>
You should receive an email. Check spam.

<ol start="5" style="list-style-type: decimal;">
<li>Undo what you did, un-fail the drive.</li></ol>

<pre>sudo mdadm /dev/md126 --remove /dev/sdb3
sudo mdadm /dev/md126 --add /dev/sdb3</pre>
<ol start="6" style="list-style-type: decimal;">
<li>Watch it re-sync. Don’t mess with anything until it is fully resynced.</li></ol>

<pre>watch cat /proc/mdstat</pre>
<span id="testing-the-setup-for-real---hardware-fault."></span>