Editing Introduction to a Self Managed Life: a 13 hour & 28 minute presentation by FUTO software (section)

==== 5.4 Testing the setup for real - hardware fault. ====

Now, let’s test this setup. Unplug one of the drives and see if you get a failure alert. Obviously, don’t do this after you start storing anything important on here. We do this in the build phase of our system to make sure it works, BEFORE trusting this system with anything important.

# 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>
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<li>If no false positives, unplug the drive from the running system.</li></ol>

<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 after plugging it back in..</li></ol>

<pre>sudo mdadm /dev/md126 --remove /dev/sdb3
sudo mdadm /dev/md126 --add /dev/sdb3</pre>
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<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="step-6-backup-strategy"></span>