The above is a great answer. To expand on this (from some googling). All of this requires root. 1) Create a sparse file (actual size depends on usage) trun

The above is a great answer. To expand on this (from some googling). All of this requires root. 1) Create a sparse file (actual size depends on usage) truncate -s 100G /home/zzz/Dropbox.image 2) Create a ext4 filesystem on it mkfs.ext4 -m0 /home/zzz/Dropbox.image 3) Mount it as a loopback file system sudo mount /home/zzz/Dropbox.image /home/zzz/Dropbox-fs 4) Create / Copy your dropbox folder to Dropbox-fs sudo mkdir /home/zzz/Dropbox-fs/Dropbox sudo chown -R zzz.zzz /home/zzz/Dropbox-fs/Dropbox cp -r /home/zzz/Dropbox-original /home/zzz/Dropbox-fs/Dropbox 5) Start Dropbox and point it to the new location 6) If we want to mount this automatically at login. Adding it to /etc/fstab may not work because of encryption. But perhaps some script at login to mount it will work. For example, we can create a script at /usr/local/bin/mountDB.sh and then add a line to /etc/sudoers zzz ALL=(root) NOPASSWD: /usr/local/bin/mountDB.sh Then somehow call this script at login of user zzz.