Beard at 05:56, 8 August 2018

2018-08-08T05:56:47Z

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<div class="redbox">
Unfinished page...
</div>

I wanted to build a small Network Attached Storage (NAS) that is small, portable, cheap, and and doesn't consume a lot of power. I decided to use a Raspberry Pi 2 with a 500GB mechanical hard drive attached via USB. The purpose of this project is to have my most important files backed up on a portable device that I can grab in case of a fire.

__TOC__

= Hardware =

== Parts list ==

* Raspberry Pi 2 Model B ([https://www.raspberrypi.org/products/raspberry-pi-2-model-b/ link])
* 4GB Sandisk SD card ([https://www.google.com/search?q=sandisk+4gm+mini+sd+card&source=univ&tbm=shop&tbo=u&sa=X&ved=0ahUKEwiB1cK0_L3bAhU4BjQIHYQVDX0QsxgIKA&biw=1360&bih=662 link])
* 500GB 2.5 inch hard drive ([https://www.google.com/search?biw=1360&bih=662&tbm=shop&ei=hEQXW4nLMYS40PEP3vC88Ao&q=wd+2.5+inch+500gb+sata&oq=wd+2.5+inch+500gb+sata&gs_l=psy-ab.3...7549.9805.0.10148.5.5.0.0.0.0.78.273.5.5.0....0...1c.1.64.psy-ab..0.0.0....0.EbFCuk0_VQk link])
* SATA-to-USB adapter ([https://www.google.com/search?biw=1360&bih=662&tbm=shop&ei=30UXW4GjKqrA0PEPqsGZcA&q=WEme+USB+3.0+to+SATA+&oq=WEme+USB+3.0+to+SATA+&gs_l=psy-ab.3...2773.2773.0.2985.1.1.0.0.0.0.43.43.1.1.0....0...1c.1.64.psy-ab..0.0.0....0.tO9Rt9xzUhU link])
* LM2596S DC-to-DC buck converter ([https://www.google.com/search?biw=1360&bih=662&tbm=shop&ei=nkUXW9g74r3Q8Q_5sLf4CA&q=LM2596S&oq=LM2596S&gs_l=psy-ab.3..0.18061.18061.0.18356.1.1.0.0.0.0.46.46.1.1.0....0...1c.1.64.psy-ab..0.1.46....0.3n3WQkFguXI link])
* CD drive enclosure (thrift store)
* 12V DC power supply ([https://www.google.com/search?biw=1360&bih=662&tbm=shop&ei=E0UXW97SLaSM0PEPwZC_yA4&q=12v+laptop+ac+adapter+-19v&oq=12v+laptop+ac+adapter+-19v&gs_l=psy-ab.3...9711.10981.0.11085.5.5.0.0.0.0.48.206.5.5.0....0...1c.1.64.psy-ab..0.0.0....0.zSxuwLB_tV4 link])
* various parts (USB cable, nuts/bolts, etc.)

== <span id="Power_Supply"></span>Power ==

The Raspberry Pi requires a little more than 5V and the USB-to-SATA adapter requires 12V, so I'm using a 12V DC power supply and a DC-to-DC buck converter (LM2596S) to convert it to 5V. Notice the placement of glue on the SATA port (second photo below) to prevent things from coming loose. I also put glue on the potentiometer on the buck converter after dialing it in to about 5.4V.

[[File:DSC00539.JPG|frameless|400px]]
[[File:DSC00679.JPG|frameless|400px]]<br/>
<i>Note: the hard drives are different colors because I switched hard drives half way through the project.</i>

The whole power setup is wired like this:

[ wiring diagram ]

Another thing that I did was add a tactile button to the back as a way of shutting down and restarting the machine. I mapped it to GPIO04 on the Raspberry Pi. For software setup, see [[#offbtn|Off Button Script]].

== Hard Drive ==

The hard drive is a 500GB 2.5 inch mechanical drive, attached via USB with a SATA to USB adapter. I mounted it under the Raspberry Pi using 3D printed brackets ([https://www.thingiverse.com/thing:2976706 link]).

[[File:DSC00478.JPG|frameless|400px]]
[[File:DSC00480.JPG|frameless|400px]]

The adapter is a <i>WEme USB 3.0 to SATA Converter Adapter (model number 4328317644)</i> that I bought from Amazon (here's a Google [https://www.google.com/search?biw=1360&bih=662&tbm=shop&ei=30UXW4GjKqrA0PEPqsGZcA&q=WEme+USB+3.0+to+SATA+&oq=WEme+USB+3.0+to+SATA+&gs_l=psy-ab.3...2773.2773.0.2985.1.1.0.0.0.0.43.43.1.1.0....0...1c.1.64.psy-ab..0.0.0....0.tO9Rt9xzUhU link]). I took the casing off of it and just used the bare PCB. The reason I chose this particular adapter is that it uses external power instead of being powered through the USB. The Raspberry Pi can only provide so much current. The adapter came with a 12V power supply, but I replaced it with higher current adapter.

[[File:Hdd-usb-adapter.jpg|frameless|300px]]
[[File:DSC00535.JPG|frameless|400px]]

I decided to solder the USB cable to the Pi instead of plugging it into the USB port. I found that I still needed to wire up all four USB pins to the Raspberry Pi because the adapter still expects there to be power on the USB. I also soldered the cable shielding to one of the USB anchor points on the Raspberry Pi.

[[File:DSC00676.JPG|frameless|400px]]<br/>
<i>Notice that I put kapton tape under the wire as well as on top.</i>

Here is the USB wiring diagram:

[ USB pinout diagram ]

Wiring it up this way presents the risk of accidentally plugging something into the USB port in the back that is used for the hard drive, so I 3D printed a USB cover. The port that needs to be blocked is the top right next to the Ethernet port.

[[File:DSC00747_EDIT.JPG|frameless]]
[[File:DSC00828.JPG|frameless]]<br/>
<i>Not my design ([https://www.thingiverse.com/thing:2655623 link]).</i>

== LED Indicator ==

I put an RGB LED on the front of the case as an indicator light.

[[File:DSC00681.JPG|frameless|400px]]

<table>
<tr>
<td style="padding-right:10px;">
<b>Here is the GPIO Pinout:</b>

<table class="nice">
<tr>
<th>LED Pin</th>
<th style="width:140px;">GPIO Pin</th>
</tr>

<tr>
<td>blue</td>
<td>GPIO23</td>
</tr>

<tr>
<td>red</td>
<td>GPIO18</td>
</tr>

<tr>
<td>GND</td>
<td>GND</td>
</tr>
</table>

</td>
<td>

<b>Here are the current ways this LED indicates status:</b>

<table class="nice">
<tr>
<th>Color</th>
<th>Behavior</th>
<th style="width:140px;">Meaning</th>
</tr>

<tr>
<td>blue</td>
<td>solid</td>
<td>system idle</td>
</tr>

<tr>
<td>blue</td>
<td>blink</td>
<td>backup in progress</td>
</tr>

<tr>
<td>red</td>
<td>blink</td>
<td>backup error occurred</td>
</tr>
</table>

</td></tr>
</table>

For software setup of the LED indicator, see [[#ledscript|LED Script]].

== Enclosure ==

The enclosure is simply an old external CD/DVD drive enclosure. I cut out a place in the back for the Raspberry Pi USB and Ethernet connectors. I glued on a piece of black acrylic on the front of the case as a face plate. The internals are mounted to a piece of MDF board which is bolted in from the bottom. It was really just trial and error figuring out how to mount everything. I ended up making 3D printed parts for the hard drive.

[[File:DSC00682.JPG|frameless|400px]]
[[File:DSC00680.JPG|frameless|400px]]

Notice the stand-offs on the Raspberry Pi have segments of drinking straw on them. This was simply to ensure the nuts were put on at exactly the same height; the straw segments were all cut exactly the same length and were used as guides. I could have cut them off, but it wasn't necessary.

[[File:DSC00475.JPG|frameless|400px]]
[[File:DSC00827.JPG|frameless|400px]]

= Software =

== <span id="OperatingSystem"></span>Operating System ==

I used a minimal install of Raspbian Jessie. You can download the latest version of Raspbian [https://www.raspberrypi.org/downloads/raspbian/ here]. There are several configurations I setup for this project. I do these tasks as root.

I installed all the packages that I'm going to use in this project:
<pre>
apt-get install python python-rpi.gpio python-pylibacl python-pylibattr python-pyxattr rdiff-backup ssmtp
</pre>

I added the user and the group that will be performing the backup (I typically don't use the system's built-in accounts):
<syntaxhighlight lang="shell">
# Assuming your password is 'PICKLES', but you should run passwd manually and enter the password in the prompt
useradd -m backer
echo -e "PICKLES\nPICKLES" | passwd backer
</syntaxhighlight>

I created a mount point for the backups and setup permissions:
<syntaxhighlight lang="shell">
mkdir /backups
chown backer:backer /backups
chmod 770 /backups
</syntaxhighlight>

I setup the drive:
<syntaxhighlight lang="shell">
# Find out the drive name
# Mine was /dev/sda but for basic copy/paste safety I will use /dev/sdx in these examples
fdisk -l | grep "^Disk"

# Create the partition /dev/sdx1
echo -e "n\np\n1\n\n\n\nw\n" | fdisk /dev/sdx

# Create file system with 0% reserved blocks on sdx1
mkfs -t ext4 -m 0 -L Backups01 /dev/sdx1

# Add the mount to fstab. Importantly, I'm using the 'nofail' and 'nobootwait' options.
echo 'LABEL="Backups01" /backups ext4 defaults,nofail,nobootwait 0 0' >>/etc/fstab
mount -a
</syntaxhighlight>

On the <b>source</b> machine (the remote machine that has my files) I also create the user:
<syntaxhighlight lang="shell">
# Assuming your password is 'PICKLES'
useradd -m backer
echo -e "PICKLES\nPICKLES" | passwd backer
</syntaxhighlight>

The tricky part is making sure that backer has read permissions on all the files that you need to backup, and read/execute permissions on folders. So if I assume your files are contained in /home/timmy/myfiles (on the <b>source</b> machine), you might do:
<syntaxhighlight lang="shell">
# Add group ownership to all files/folders
chown -R :backer /home/timmy/myfiles
# Add read/execute to all folders
find /home/timmy/myfiles -type d -print0 | xargs -0 chmod g+rx
# Add read to all files
find /home/timmy/myfiles -type f -print0 | xargs -0 chmod g+r
</syntaxhighlight>

You can set permissions on a more granular level if you need to. Don't do this on system files.

[ incomplete: source server ssh config and certificate ]

== Backup Script ==

This is the main script that I wrote to perform the backups. Make sure you've installed the packages mentioned in [[#OperatingSystem|Operating System]].

Here's the idea:
* The <b>backup</b> server has a cron job that performs the backup process on a schedule.
* The backup process logs in remotely to the <b>source</b> server using rdiff-backup.
* Rdiff-backup uses SSH. We will be able to log in without a password prompt by using certificate authentication.
* We define <i>included</i> and <i>excluded</i> files and directories to control what get backed up incrementally.
* Each backup process generates a log file and sends text and email notifications if an error occurs.

As root, I created the directory structure:
<pre>
mkdir -p /scripts/backup-system/config /scripts/config /logs/backups
</pre>

crontab
<pre>
10 4 * * * root /scripts/backup-system/backup-run.sh -y
</pre>

<div class="fix">
Re-upload scripts after I've fixed everything.
</div>
[ incomplete ]

== <span id="ledscript"></span>LED Script ==

== Backup Status Script ==

== Restore Script ==

== <span id="TextandEmailMessaging"></span>Text and Email Messaging ==

I wanted the system to send me text and email notifications.

Make sure you've installed the packages mentioned in [[#OperatingSystem|Operating System]].

crontab
<pre>
00 12 * * * root /scripts/scheduled-messages.sh
</pre>

[ incomplete ]

== <span id="offbtn"></span>Off Button Script ==

I added a tactile button to GPIO4 on the Raspberry Pi to act as a power button. When held for a certain number of seconds, it executes the shutdown command. This allows my [[#ShutdownScript|Shutdown Script]] to wait for a backup to complete before powering the system down.

Here is the Python script:
<syntaxhighlight lang="python">
#!/bin/python
#
# Script to shutdown Raspberry Pi when GPIO input is held.
# Connect a button between ground (GND) and the GPIO pin
# that you specify below.
#
# If you run this script from your /etc/rc.local file, it
# will be running as root, which eliminates the need to
# enter a password to elevate privileges. Otherwise, the
# sudo command will ask for a password before it will
# execute shutdown.

import RPi.GPIO as GPIO
import sys,os,signal,time

# GPIO pin number
btn = 4

# Button must be held for this many seconds
delay = 3.0

def sense_input(btn,delay):

try:
# Wait for button press
GPIO.wait_for_edge(btn, GPIO.FALLING)

count = 0
while True:
if GPIO.input(btn) == False:
if count < delay:
count = count + 1
time.sleep(0.1)
continue
else:
# Shutdown system
os.system("sudo shutdown -h now")
os._exit(-1)
else:
try:
GPIO.cleanup()
except:
pass
time.sleep(0.1)
break

except KeyboardInterrupt:
try:
GPIO.cleanup()
except:
pass
os._exit(-1)

except:
pass

delay = delay*10
while True:
GPIO.setmode(GPIO.BCM)
GPIO.setup(btn, GPIO.IN, pull_up_down=GPIO.PUD_UP)
sense_input(btn,delay)
</syntaxhighlight>

Assuming you save this to <code>/scripts/off-button.py</code> go ahead and make it executable:
<pre>
chmod a+x /scripts/off-button.py
</pre>

Then add it to <code>/etc/rc.local</code> so it runs on startup. Enter the command above the <code>exit 0</code> line so that it looks like this:
<syntaxhighlight lang="shell">
# ... existing rc.local stuff ...

python /scripts/off-button.py &
exit 0
</syntaxhighlight>

== <span id="ShutdownScript"></span>Shutdown Script ==

I wanted to have the system wait for a backup to complete if the system is shutdown while a backup is in progress. I created this script called <code>wait-for-backup</code>. It also sends a text message on shutdown (see [[#TextandEmailMessaging|Text and Email Messaging]]):
<syntaxhighlight lang="shell">
#!/bin/bash
#
# Shutdown script for backup server.
# Waits for rdiff-backup to finish.
#

log=/logs/server-shutdown.log

mount -oremount,rw /
echo "[`date`] TEST: Shutdown issued. Waiting for rdiff-backup to stop..." >>$log

/scripts/sms.sh "backup2" "system shutdown ( `date` )"
sleep 20

echo "[`date`] TEST: Done waiting." >>$log
mount -oremount,ro /
</syntaxhighlight>

Once you have this script located in <code>/etc/init.d</code> you can create a symbolic link in the appropriate rc directories. Make sure this script is run before any of the VirtualBox services are stopped. For my server, I made it <b>K64</b>. Make sure wait-for-backup is executable.

<syntaxhighlight lang="shell">
sudo chmod 755 /etc/init.d/wait-for-backup
sudo ln -s /etc/init.d/wait-for-backup /etc/rc0.d/K64stop-vms
sudo ln -s /etc/init.d/wait-for-backup /etc/rc6.d/K64stop-vms
</syntaxhighlight>

<b>If you're using Systemd</b> you need to do this differently.

You can put a script in the Systemd system-shutdown script folder. It is located in a different place on different Linux distributions:
* Debian: <code>/lib/systemd/system-shutdown</code>
* Other: <code>/usr/lib/systemd/system-shutdown</code>

Put the wait-for-backup script in that folder and make sure it's executable.

<div class="red-box">

[ THIS SECTION NEEDS TO BE CORRECTED ]

You actually make script <code>/scripts/backup-system/shutdown-wait-for-backup.sh</code>
<syntaxhighlight lang="shell">
contents
</syntaxhighlight>

Then make file <code>/lib/systemd/system/wait-for-backup.service</code> with:
<syntaxhighlight lang="shell">
contents
</syntaxhighlight>
</div>

= Links =

* https://www.tecmint.com/rdiff-backup-remote-incremental-backup-for-linux/
* https://www.howtoforge.com/linux_rdiff_backup
* http://www.linuxproblem.org/art_9.html
* http://www.nongnu.org/rdiff-backup/examples.html

Backup NAS Mini - Revision history

Beard at 05:56, 8 August 2018