Do you have a few old external USB drives lying around collecting dust? Well, you could put them to good use with a simple and robust NAS (Network-attached storage) using a Rasberry Pi.
Moreover, if you have plenty of old travel photos on that external drive, you could host my open source NodeJS app (GitHub repo here) to display them on an old tablet, just like an interactive smart photo frame.

I've tested this on Rasberry Pi 3 and 4, but really any should work. If your external USB drive has it's own power source, you can connect it to RPi directly, but if it doesn't have it's own power source, you might need an externally powered USB hub to which you'll connect your USB drives. Raspberry might not be able to suply enough current to power more than 2-3 external USB drives.

Prerequisites

I assume you already have Raspberry Pi OS installed, but if not, install it from official source https://www.raspberrypi.com/software/ (make sure you enable SSH during intallation).
If you already have a different Linux distribution installed, this should also work, but you might need to slightly modify some of below commands.

1. ssh to your RPi and update your system

   sudo apt update && sudo apt full-upgrade
   

2. Connect any USB drives you want to make accessible over the network.
   Raspberry Pi OS should automatically detect USB drives when you plug them in. To see what drives it found run:

   sudo blkid
   
   /dev/mmcblk0p1: LABEL_FATBOOT="boot" LABEL="boot" UUID="17B6-FC00" BLOCK_SIZE="512" TYPE="vfat" PARTUUID="834cc527-01"
   /dev/mmcblk0p2: LABEL="rootfs" UUID="b101bb80-3338-4b94-a775-b3844f8f2aa8" BLOCK_SIZE="4096" TYPE="ext4" PARTUUID="834cc527-02"
   /dev/sdc1: LABEL="SAMSUNG" BLOCK_SIZE="512" UUID="8E84B2B084B29A63" TYPE="ntfs" PARTUUID="01022cb5-01"
   /dev/sdd1: LABEL="SAMSUNG" BLOCK_SIZE="512" UUID="1E904FEC904FC8CB" TYPE="ntfs" PARTUUID="d9d225e4-01"
   /dev/sdb1: LABEL="Elements" BLOCK_SIZE="512" UUID="DC74B02074AFFB80" TYPE="ntfs" PARTLABEL="Elements" PARTUUID="ae55a0c1-17a6-41a5-bf6f-c4d86a960b7e"
   /dev/sda1: LABEL="SAMSUNG" BLOCK_SIZE="512" UUID="0C6EBE646EBE466C" TYPE="ntfs" PARTUUID="411e3984-01"
   

   or

   ls -l /dev/disk/by-uuid
   
   lrwxrwxrwx 1 root root 10 Aug 11 20:28 0C6EBE646EBE466C -> ../../sda1
   lrwxrwxrwx 1 root root 15 Aug  9 22:07 17B6-FC00 -> ../../mmcblk0p1
   lrwxrwxrwx 1 root root 10 Aug  9 22:08 1E904FEC904FC8CB -> ../../sdd1
   lrwxrwxrwx 1 root root 10 Aug  9 22:08 8E84B2B084B29A63 -> ../../sdc1
   lrwxrwxrwx 1 root root 15 Aug  9 22:07 b101bb80-3338-4b94-a775-b3844f8f2aa8 -> ../../mmcblk0p2
   lrwxrwxrwx 1 root root 10 Aug 11 20:28 DC74B02074AFFB80 -> ../../sdb1
   

   for a bit more visual representation, try:

   lsblk
   
   NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
   sda           8:0    0   1.8T  0 disk
   └─sda1        8:1    0   1.8T  0 part /media/pi/SAMSUNG2
   sdb           8:16   0   3.6T  0 disk
   └─sdb1        8:17   0   3.6T  0 part /media/pi/Elements
   sdc           8:32   0 931.5G  0 disk
   └─sdc1        8:33   0 931.5G  0 part /media/pi/SAMSUNG1
   sdd           8:48   0 931.5G  0 disk
   └─sdd1        8:49   0 931.5G  0 part /media/pi/SAMSUNG
   mmcblk0     179:0    0  29.7G  0 disk
   ├─mmcblk0p1 179:1    0   256M  0 part /boot
   └─mmcblk0p2 179:2    0  29.5G  0 part /
   

   We're interested in /dev/sda1, /dev/sdb1, /dev/sdc1 and /dev/sdd1
   Make a note of UUID for each drive you want to use.

3. Create folders for each drive, where you'll see their contents

   sudo mkdir /mnt/nas1
   sudo chown -R pi:pi /mnt/nas1
   

   Repeat above for each drive, you're configuring.

4. Install missing dependiencies
   Make sure your system is able to read NTFS partisions by installing ntfs-3g package It should already be there if you're using original Raspberry Pi OS. If not install it.

   sudo apt install ntfs-3g
   

   You might need to also install Extended FAT package to read FAT partitions.

   sudo apt install exfat-fuse exfat-utils
   

5. Create a user that will access mounted drives
   I'm creating a new user called "nas" for the purpose of accessing NAS resources over network.

   sudo useradd nas
   sudo passwd nas
   
   New password:
   Retype new password:
   passwd: password updated successfully
   

   Find out new user's id and group id.

   id -u nas
   id -g nas
   

   In my case both returned "1001".

6. Automatically mount drives
   Now that we have all the dependencies installed, we need to make sure our drives mount automatically after system restart.

   sudo vim.tiny /etc/fstab
   

   which if unmodified, should look similar to this:

   proc            /proc           proc    defaults          0       0
   PARTUUID=834cc527-01  /boot           vfat    defaults,flush    0       2
   PARTUUID=834cc527-02  /               ext4    defaults,noatime  0       1
   # a swapfile is not a swap partition, no line here
   #   use  dphys-swapfile swap[on|off]  for that
   

   Don't change any of that, just leave it as it is and add your entries below. Remember to change the values of UUID, uid and gid with the values we noted before.

   # Drive 1 - 2T
   UUID=0C6EBE646EBE466C /mnt/nas1 auto nofail,uid=1001,gid=1001,noatime 0 0
   
   # Drive 2 - 1T
   UUID=1E904FEC904FC8CB /mnt/nas2 auto nofail,uid=1001,gid=1001,noatime 0 0
   
   # Drive 3 - 1T
   UUID=8E84B2B084B29A63 /mnt/nas3 auto nofail,uid=1001,gid=1001,noatime 0 0
   
   # Drive 4 - 4T
   UUID=DC74B02074AFFB80 /mnt/nas4 auto nofail,uid=1001,gid=1001,noatime 0 0
   

   Your system might have automatically mounted all the drives or if you're debugging or changing something and you had your drive already mounted, you'll have to unmount it and mount it again for the changes to take effect.

   sudo umount /dev/sda1
   sudo umount /dev/sdb1
   sudo umount /dev/sdc1
   sudo umount /dev/sdd1
   

   Mount defined drives

   sudo mount -av
   
   /proc                    : already mounted
   /boot                    : already mounted
   /                        : ignored
   /mnt/nas1                : successfully mounted
   /mnt/nas2                : successfully mounted
   /mnt/nas3                : successfully mounted
   /mnt/nas4                : successfully mounted
   

   Now we have drives mounted that should persist over system restarts.

Share mounted drives on local network

1. Install Samba
   Samba is a suite of applications that implements the Server Message Block (SMB) protocol. Many operating systems, including Microsoft Windows, use the SMB protocol for client-server networking. Samba enables Linux / Unix machines to communicate with Windows machines in a network, which in our case simply means sharing that mounted drive(s) over network.

   sudo apt install samba samba-common-bin cifs-utils
   

2. Create samba user
   Remember we created a new system user nas, now we need to make it a Samba user. The password we created before for that user was for RPi OS, now you can specify a different password to use when accessing your resources over network. You can keep passwords the same for ease of use.

   sudo smbpasswd -a nas
   New SMB password:
   Retype new SMB password:
   Added user nas.
   

   The -a switch adds user nas to the Samba password list.
   If you need to modify existing Samba user you can do it with:

   sudo smbpasswd nas
   

   To list existing samba users run:

   sudo pdbedit -L -v
   

3. Configure network shareable resource
   Open Samba config file

   sudo vim.tiny /etc/samba/smb.conf
   

   Go to the bottom of the file and add

   [nas1]
   comment = My USB drive 2T
   path = /mnt/nas1
   # you can list multiple users here separated by space
   valid users = nas
   force group = users
   create mask = 0660
   directory mask = 0771
   read only = no
   # if you need unathenticated access (guest users), uncomment below line
   # guest ok = yes
   

   Add a section like this for each of your drives. Changing the group name [nas1] and path accordingly.
   Test if the config is correct

   testparm
   
   Load smb config files from /etc/samba/smb.conf
   Loaded services file OK.
   Weak crypto is allowed
   Server role: ROLE_STANDALONE
   

   If everything is ok, restart Samba to apply new settings

   sudo systemctl restart smbd
   

   In case of any issues or simply if you want to see active connections, run:

   sudo smbstatus
   

Map drive on Windows

1. Open file manager
2. Go to "This PC"
3. At the top in "Computer" tab, click on "Map network drive", not the "Add network location". There's a key difference.
4. Choose a Drive letter you want to assign to this resource.
5. In "Folder" field type in \\RASPBERRYPI\nas1 or whatever location your Raspberry is at
6. Leave "Reconnect at sign-in" ticked.
7. Click Finish

On the credentials popup, Windows will most likely prefil your current user details. If that's the case click "More choices" and then "Use a different account". This will allow you to specify your Samba username and password. For us the user was nas.

Map drive on Linux

If you want to access local drives on Linux (or Mac) it should be very similar to what we've done before.

sudo apt install cifs-utils
sudo mkdir /mnt/nas1
sudo mkdir /mnt/nas2
sudo mkdir /mnt/nas3
sudo mkdir /mnt/nas4
sudo vim /etc/fstab

Add below lines to the bottom of fstab file

//192.168.0.100/nas1  /mnt/nas1 cifs    uid=0,username=nas,password=******,iocharset=utf8,file_mode=0777,dir_mode=0777,sec=ntlmssp  0  0
//192.168.0.100/nas2  /mnt/nas2 cifs    uid=0,username=nas,password=******,iocharset=utf8,file_mode=0777,dir_mode=0777,sec=ntlmssp  0  0
//192.168.0.100/nas3  /mnt/nas3 cifs    uid=0,username=nas,password=******,iocharset=utf8,file_mode=0777,dir_mode=0777,sec=ntlmssp  0  0
//192.168.0.100/nas4  /mnt/nas4 cifs    uid=0,username=nas,password=******,iocharset=utf8,file_mode=0777,dir_mode=0777,sec=ntlmssp  0  0

Remember to change the IP address to whatever your local RPi is using. The username and password should probably be stored in a separate file, but just to keep things simple, I'll leave it inline.
Mount your drives

sudo mount -av

If you want to avoid situation when after server restart you have to start lots of services manually, a little thing like chkconfig would come in handy.
First you might want to take a look at a list of services handled by chkconfig:

chkconfig --list

You should see something like this:

mysql 0:off 1:off 2:on 3:on 4:on 5:on 6:off
named 0:off 1:off 2:off 3:on 4:off 5:off 6:off
sshd 0:off 1:off 2:on 3:on 4:on 5:on 6:off

To add for example mysql to autostart list simply type:

chkconfig --add mysql on

To remove a service from autostart list type:

chkconfig --del mysql

For full list of chkconfig options go here.

Install dependancy

Before we install memcached we need a dependency library libevent. Check for latest stable version at https://monkey.org/~provos/libevent/

cd /usr/local/src
wget http://monkey.org/~provos/libevent-1.4.13-stable.tar.gz
tar -xzvf libevent-1.4.13-stable.tar.gz
cd libevent-1.4.13-stable
./configure --prefix=/usr/local
make
make install
cd ..

Install memcached

Check for latest stable version at https://memcached.org/

wget http://memcached.googlecode.com/files/memcached-1.4.4.tar.gz
tar -xzvf memcached-1.4.4.tar.gz
cd memcached-1.4.4
LDFLAGS='-Wl,--rpath /usr/local/lib'
./configure --prefix=/usr/local
make
make install

More information about LDFLAGS https://en.wikipedia.org/wiki/Linker

Run memcached as a daemon

Basic options: d = daemon, m = memory, u = user, l = IP to listen to, p = port

memcached -u root -d

or

memcached -u root -d -m 512 -l 127.0.0.1 -p 11211

To stop daemon type

pkill memcached

Now we’re off to installing php extension memcache.

xmpppy is a Python library allowing you to send messages from your server to any Jabber enabled communicator.
Firstly download and unpack xmpppy to a local directory. Next go into the unpacked directory and run:

python setup.py install

Next you need a script that will do the sending. Use your favourite text editor to create file i.e.:

vim xsend.py

Just paste below script which was taken from original site. Create another jabber account that you’ll send messages from and remember to change values in line 20 to those new login details.

#!/usr/bin/python
# $Id: xsend.py,v 1.8 2006/10/06 12:30:42 normanr Exp $ 
import sys,os,xmpp,time
if len(sys.argv) < 2:
    print "Syntax: xsend JID text"
    sys.exit(0)

tojid=sys.argv[1]
text=' '.join(sys.argv[2:])

jidparams={}
if os.access(os.environ['HOME']+'/.xsend',os.R_OK):
    for ln in open(os.environ['HOME']+'/.xsend').readlines():
        if not ln[0] in ('#',';'):
            key,val=ln.strip().split('=',1)
            jidparams[key.lower()]=val
for mandatory in ['jid','password']:
    if mandatory not in jidparams.keys():
        open(os.environ['HOME']+'/.xsend','w').write('#Uncomment fields before use and type in correct credentials.\n#JID=romeo@montague.net/resource (/resource is optional)\n#PASSWORD=juliet\n')
        print 'Please point ~/.xsend config file to valid JID for sending messages.'
        sys.exit(0)

jid=xmpp.protocol.JID(jidparams['jid'])
cl=xmpp.Client(jid.getDomain(),debug=[])

con=cl.connect()
if not con:
    print 'could not connect!'
    sys.exit()
print 'connected with',con
auth=cl.auth(jid.getNode(),jidparams['password'],resource=jid.getResource())
if not auth:
    print 'could not authenticate!'
    sys.exit()
print 'authenticated using',auth

#cl.SendInitPresence(requestRoster=0)   # you may need to uncomment this for old server
id=cl.send(xmpp.protocol.Message(tojid,text))
print 'sent message with id',id

time.sleep(1)   # some older servers will not send the message if you disconnect immediately after sending

#cl.disconnect()

All you need to do now is to run the script 🙂 First run will create a file in your home directory which should contain username and password from line 20. Second run should accually send the message.

./xsend.py your_main_jabber@your_jabber.com Hello world!

Now set up your monitoring scripts that will send you jabber messages when something goes wrong.