Home folder is only for my stuff like git cloning, compiling or some temporary stuff. The rest is on var and usr foders like you intended to be. I didn't change content of anything in these folders after installation of SnakeOil OS but something removes the scanned database when reboot command is issued on mympd system web page or trough sudo reboot.
Also when I mount NFS share it gets removed from mounted list after reboot so I added my NFS share on fstab.
Here's content of var/www/players and usr/local/bin folders:
milan@snakeoilos:/var/www/players $ ls -l
total 64
drwxr-xr-x 2 www-data www-data 4096 Dec 12 00:22 clementine
drwxr-xr-x 2 www-data www-data 4096 Dec 12 00:22 lms
drwxr-xr-x 2 www-data www-data 4096 Dec 12 00:22 mpd-dsd-018
drwxr-xr-x 2 www-data www-data 4096 Dec 14 14:35 mpd-SACD
drwxr-xr-x 2 www-data www-data 4096 Dec 12 00:22 mpd-v21
drwxr-xr-x 2 www-data www-data 4096 Dec 12 00:22 mpd-v22
drwxr-xr-x 2 www-data www-data 4096 Dec 12 00:22 mpd-v23
drwxr-xr-x 2 www-data www-data 4096 Dec 12 00:22 NAA
drwxr-xr-x 2 www-data www-data 4096 Dec 12 00:22 qmmp
drwxr-xr-x 2 www-data www-data 4096 Dec 12 00:22 RoonBridge
drwxr-xr-x 2 www-data www-data 4096 Dec 12 00:22 RoonServer
drwxr-xr-x 2 www-data www-data 4096 Dec 12 00:22 Squeezelite-R2
drwxr-xr-x 2 www-data www-data 4096 Dec 12 00:22 Squeezelite-ralph
drwxr-xr-x 2 www-data www-data 4096 Dec 12 00:22 Squeezelite-v1.6.4-test
drwxr-xr-x 2 www-data www-data 4096 Dec 12 00:22 Squeezelite-v1.8
drwxr-xr-x 2 www-data www-data 4096 Dec 12 00:22 upmpdcli
milan@snakeoilos:/var/www/players $ cd mpd-SACD
milan@snakeoilos:/var/www/players/mpd-SACD $ ls -l
total 200644
-rwxr-xr-x 1 www-data www-data 463 Dec 12 01:14 config
-rwxr-xr-x 1 www-data www-data 4170 Aug 18 18:29 init
-rwxr-xr-x 1 www-data www-data 110 Aug 18 18:38 install.sh
-rwxr-xr-x 1 www-data www-data 68116928 Dec 14 14:35 mpd
-rwxr-xr-x 1 www-data www-data 69171560 Nov 19 23:26 mpd.bak
-rwxr-xr-x 1 www-data www-data 12766 Aug 18 18:42 mpd.conf.template
-rwxr-xr-x 1 www-data www-data 68116896 Aug 18 18:50 mpd_old
-rwxr-xr-x 1 www-data www-data 201 Aug 18 18:29 start
-rwxr-xr-x 1 www-data www-data 312 Aug 18 18:29 stop
-rwxr-xr-x 1 www-data www-data 111 Aug 18 18:43 uninstall.sh
Within new mpd-SACD folder I've copied files from mpd-v23 folder and adjusted content of some of the scripts to reflect change of folder name.
But regardless of version of mpd used I can't retain scanned database.
Here is output of sudo mount:
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
proc on /proc type proc (rw,relatime)
udev on /dev type devtmpfs (rw,nosuid,relatime,size=3730692k,nr_inodes=932673,mode=755)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs on /run type tmpfs (rw,nosuid,nodev,noexec,relatime,size=799736k,mode=755)
/dev/mmcblk0p2 on / type ext4 (rw,noatime)
securityfs on /sys/kernel/security type securityfs (rw,nosuid,nodev,noexec,relatime)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
tmpfs on /run/lock type tmpfs (rw,nosuid,nodev,noexec,relatime,size=5120k)
cgroup2 on /sys/fs/cgroup type cgroup2 (rw,nosuid,nodev,noexec,relatime,nsdelegate,memory_recursiveprot)
pstore on /sys/fs/pstore type pstore (rw,nosuid,nodev,noexec,relatime)
bpf on /sys/fs/bpf type bpf (rw,nosuid,nodev,noexec,relatime,mode=700)
systemd-1 on /proc/sys/fs/binfmt_misc type autofs (rw,relatime,fd=30,pgrp=1,timeout=0,minproto=5,maxproto=5,direct,pipe_ino=392)
mqueue on /dev/mqueue type mqueue (rw,nosuid,nodev,noexec,relatime)
tracefs on /sys/kernel/tracing type tracefs (rw,nosuid,nodev,noexec,relatime)
debugfs on /sys/kernel/debug type debugfs (rw,nosuid,nodev,noexec,relatime)
configfs on /sys/kernel/config type configfs (rw,nosuid,nodev,noexec,relatime)
fusectl on /sys/fs/fuse/connections type fusectl (rw,nosuid,nodev,noexec,relatime)
ramfs on /run/credentials/systemd-sysctl.service type ramfs (ro,nosuid,nodev,noexec,relatime,mode=700)
ramfs on /run/credentials/systemd-sysusers.service type ramfs (ro,nosuid,nodev,noexec,relatime,mode=700)
ramfs on /run/credentials/systemd-tmpfiles-setup-dev.service type ramfs (ro,nosuid,nodev,noexec,relatime,mode=700)
/dev/mmcblk0p1 on /boot/firmware type vfat (rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=ascii,shortname=mixed,errors=remount-ro)
ramfs on /run/credentials/systemd-tmpfiles-setup.service type ramfs (ro,nosuid,nodev,noexec,relatime,mode=700)
binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,nosuid,nodev,noexec,relatime)
sunrpc on /run/rpc_pipefs type rpc_pipefs (rw,relatime)
192.168.100.3:/music_PHENOM on /media/music/phenom type nfs (rw,relatime,vers=3,rsize=32768,wsize=32768,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=192.168.100.3,mountvers=3,mountport=1058,mountproto=tcp,local_lock=none,addr=192.168.100.3)
tmpfs on /run/user/1000 type tmpfs (rw,nosuid,nodev,relatime,size=799732k,nr_inodes=199933,mode=700,uid=1000,gid=1000)
milan@snakeoilos:/var/www/players/mpd-SACD $ ls -l /usr/local/bin
total 68996
-rwxr-xr-x 1 root root 3363976 Dec 12 00:22 alsabat
-rwxr-xr-x 1 root root 3473904 Dec 12 00:22 alsaloop
-rwxr-xr-x 1 root root 3802640 Dec 12 00:22 alsamixer
-rwxr-xr-x 1 root root 3982568 Dec 12 00:22 alsatplg
-rwxr-xr-x 1 root root 4010032 Dec 12 00:22 alsaucm
-rwxr-xr-x 1 root root 827 Dec 12 00:22 alsa_unmute
-rwxr-xr-x 1 root root 3438064 Dec 12 00:22 amidi
-rwxr-xr-x 1 root root 3699544 Dec 12 00:22 amixer
-rwxr-xr-x 1 root root 3595120 Dec 12 00:22 aplay
-rwxr-xr-x 1 root root 3567936 Dec 12 00:22 aplaymidi
-rwxr-xr-x 1 root root 3595120 Dec 12 00:22 arecord
-rwxr-xr-x 1 root root 3564720 Dec 12 00:22 arecordmidi
-rwxr-xr-x 1 root root 3560832 Dec 12 00:22 aseqdump
-rwxr-xr-x 1 root root 3554232 Dec 12 00:22 aseqnet
-rwxr-xr-x 1 root root 3339440 Dec 12 00:22 aserver
-rwxr-xr-x 1 root root 3759528 Dec 12 00:22 axfer
-rwxr-xr-x 1 root root 127 Dec 12 00:22 bubbleupnp_remote.sh
-rwxr-xr-x 1 root root 958368 Dec 12 00:22 curl
-rwxr-xr-x 1 root root 5663 Dec 12 00:22 curl-config
-rwxr-xr-x 1 root root 1584032 Dec 12 00:22 lms_remote
-rwxr-xr-x 1 root root 167 Dec 12 00:22 minimserver_remote.sh
-rwxr-xr-x 1 root root 1830 Dec 17 16:03 mpd_remote.sh
-rwxr-xr-x 1 root root 6430912 Dec 12 23:09 mympd
-rwxr-xr-x 1 root root 3965144 Dec 12 23:10 mympd-script
-rwxr-xr-x 1 root root 219 Dec 12 00:22 new_issue
-rwxr-xr-x 1 root root 770 Dec 12 00:22 snakeoil-server.sh
-rwxr-xr-x 1 root root 3325208 Dec 12 00:22 speaker-test
milan@snakeoilos:/var/www $ ls -l --group-directories-first
total 26472
drwxr-xr-x 6 www-data www-data 4096 Dec 12 00:22 assets
drwxr-xr-x 4 root root 4096 Dec 21 15:49 config
lrwxrwxrwx 1 root root 12 Dec 12 00:22 music -> /media/music
drwxr-xr-x 18 www-data www-data 4096 Dec 12 00:54 players
drwxr-xr-x 2 root root 4096 Dec 20 18:22 scratch
I presume config, music and scratch folders are root because of mpd is starting as root in /var/www/scratch/mpd.conf
milan@snakeoilos:/var/www/config $ ls
grub.template mpd-SACD mpd-v23 player snakeoil.db
milan@snakeoilos:/var/www/config $ ls -l
total 60
-rw-r--r-- 1 root root 1350 Dec 12 00:22 grub.template
drwxr-xr-x 2 root root 4096 Dec 20 23:32 mpd-SACD
drwxr-xr-x 2 root root 4096 Dec 15 17:33 mpd-v23
-rw-r--r-- 1 root root 10 Dec 15 17:20 player
-rw-r--r-- 1 root root 45056 Dec 21 15:49 snakeoil.db
milan@snakeoilos:/var/www/config $ ls -l ./mpd-SACD
total 644
-rw-r--r-- 1 root root 649133 Dec 20 23:32 database
-rw-r--r-- 1 root root 4 Dec 20 18:22 pid
-rw-r--r-- 1 root root 1277 Dec 17 23:38 state