PHONIEBOX_ReadOnly - AlvinSchiller/RPi-Jukebox-RFID GitHub Wiki
Phoniebox with read-only Filesystem
In order to make the Phoniebox more resilient against sudden power loss a mostly read-only filesystem helps against filesystem corruption.
First we need to mount a read-write Partition to /home/pi/RPi-Jukebox-RFID/shared/. This can bei either a further partition on the SD card or an USB drive connected to the Pi. If you want to store the shared partition on the sd card you need to first resize the main partition. In a normal raspbian install there is one small partition and one that fills the rest of the card. There is a good HOWTO on how to resize the partition here: https://www.howtoforge.com/partitioning_with_gparted
Please resize the partition AFTER the first boot of teh systtem since Raspbian tries to resize the partition on the sd card to fill the whole card this process seems to fail if there is a partition in the way.
Before the new partition can be mounted the original shared directory with its contents needs to be moved out of the way:
cd ~/RPi-Jukebox-RFID/
mv shared shared.old
mkdir shared
Then we need to find out the PARTUUID of the newly created partition with the command blkid. It should produce the following output:
pi@JukeboxJan:~/RPi-Jukebox-RFID $ blkid
/dev/mmcblk0p1: LABEL="boot" UUID="9304-D9FD" TYPE="vfat" PARTUUID="9282f822-01"
/dev/mmcblk0p2: LABEL="rootfs" UUID="29075e46-f0d4-44e2-a9e7-55ac02d6e6cc" TYPE="ext4" PARTUUID="9282f822-02"
/dev/mmcblk0p3: LABEL="shared" UUID="821fcedf-b705-4515-a5e8-2e99beefc1bf" TYPE="ext4" PARTUUID="9282f822-03"
In order to mount the rw partition to ~/RPi-Jukebox-RFID/shared/ on bootup you need to add the following line to /etc/fstab Replace the PARTUUID with teh one from your output. (Don't forget you need to sudo vi /etc/fstab to edit the file)
PARTUUID="9282f822-03" /home/pi/RPi-Jukebox-RFID/shared ext4 defaults,noatime 0 2
sudo mount -a will mount the new partition to its mountpoint.
Now adjust the ownership and permissions of the new shared directory:
sudo chown pi:www-data shared
sudo chmod 775 shared
Rsync the contents of shared.old into share:
rsync -av shared.old/* shared/
Some settings need to persist between boots, others are not necessarily persistend. Those that need to be persistent are symlinked to a new directory shared/settings, the others are symlinked to files in /var/tmp that will reside on a ramdisk.
ln -sf /var/tmp/Latest_RFID ~/RPi-Jukebox-RFID/settings
ln -sf /var/tmp/Latest_Folder_Played ~/RPi-Jukebox-RFID/settings
ln -sf /var/tmp/Latest_Playlist_Played ~/RPi-Jukebox-RFID/settings
ln -sf /var/tmp/latestID.txt ~/RPi-Jukebox-RFID/shared/
mkdir ~/RPi-Jukebox-RFID/shared/settings
mv Audio_Folders_Path Audio_Volume_Change_Step Idle_Time_Before_Shutdown Max_Volume_Limit Playlists_Folders_Path Second_Swipe ShowCover ../shared/settings/
ln -sf ~/RPi-Jukebox-RFID/shared/settings/* ~/RPi-Jukebox-RFID/settings/
Add the following lines to the fstab:
sudo vi /etc/fstab
tmpfs /var/log tmpfs nodev,nosuid 0 0
tmpfs /var/lib/samba tmpfs nodev,nosuid 0 0
tmpfs /var/lib/mpd tmpfs nodev,nosuid 0 0
tmpfs /var/cache/samba tmpfs nodev,nosuid 0 0
tmpfs /var/tmp tmpfs nodev,nosuid 0 0
tmpfs /tmp tmpfs nodev,nosuid 0 0
If you have not yet created a password for the Samba User pi, do it now, before moving the files away:
sudo smbpasswd pi
Move Samba files away and create mount point for a tmpfs:
sudo mv /var/lib/samba /var/lib/samba.save
sudo mkdir /var/lib/samba
sudo vi /etc/tmpfiles.d/smb.conf
paste
#Type Path Mode UID GID Age Argument
C /var/lib/samba/private - - - - /var/lib/samba.save/private
C /var/lib/samba/account_policy.tdb - - - - /var/lib/samba.save/account_policy.tdb
C /var/lib/samba/group_mapping.tdb - - - - /var/lib/samba.save/group_mapping.tdb
C /var/lib/samba/printers - - - - /var/lib/samba.save/printers
C /var/lib/samba/registry.tdb - - - - /var/lib/samba.save/registry.tdb
C /var/lib/samba/share_info.tdb - - - - /var/lib/samba.save/share_info.tdb
C /var/lib/samba/usershares - - - - /var/lib/samba.save/usershares
C /var/lib/samba/wins.dat - - - - /var/lib/samba.save/wins.dat
C /var/lib/samba/wins.tdb - - - - /var/lib/samba.save/wins.tdb
d /var/log/samba 0750 root adm - -
sudo vi /etc/tmpfiles.d/lighttpd.conf
paste
#Type Path Mode UID GID Age Argument
d /var/log/lighttpd 0755 www-data www-data - -
Change settings/Playlist_Folders_Path to shared/playlists
Edit /etc/mpd.conf and change log_file from /var/log/mpd/mpd.log to /var/log/mpd.log
If you need to make changes to your root filesystem in the future you need to remount it in read-write mode.
This can be done with the command mount -o remount,rw / and reversed by mount -oremount,to /
Sources: