Just wanted to free up some space and separate all of my projects.

First idea ... failed!
mksquashfs /home/tracktraps/Development/myproject1 ~/Squash/myproject1.sfs -info -progress -b 1048576 -comp xz -Xdict-size 100%
mkdir /mnt/myproject1
mount ~/Squash/myproject1.sfs /mnt/myproject1
unionfs -o allow_other,nonempty ~/.unionfs/changes/myproject1=rw:/mnt/myproject1/=ro ~/Development/Project1
Too much cpu overhead, too many folders, can't delete files, all get mixed up ...

Second idea ... failed!
dd if=/dev/zero of=~/Imgs/myproject1.btfs bs=1M count=10240
mkfs.btrfs ~/Imgs/myproject1.btfs
mount -o defaults,noatime,autodefrag,compress,compress-force,inode_cache ~/Imgs/myproject1.btfs ~/Development/Project1

Well ... little overhead, gzip compression, saved a lot of space, but fixed img size.

Third idea ... yay!
truncate -s 200G ~/Imgs/myproject1.btfs
mkfs.btrfs ~/Imgs/myproject1.btfs
mount -o defaults,noatime,autodefrag,compress,compress-force,inode_cache ~/Imgs/myproject1.btfs ~/Development/Project1

Well ... little overhead, gzip compression, saved a lot of space ... but wait ... why do my btfs files consume more and more space?
Hmm ... time for a little bash and my beloved systemd timers.

for f in `find . -type f -name "*.btfs"`
do
project=${$f%.*}
btrfs balance start -v -dusage=100 ~/Development/$project
btrfs balance start -v -musage=100 ~/Development/$project
fstrim ~/Development/$project
fallocate -d -v $f
done