There are several potential solutions to this. The question is: does this folder need to be encrypted, or not?
Not encrypted
If it does not need to be encrypted, the easiest solution is the following:
move the folder to /var/avoshare:
sudo mv /home/avo/share /var/avoshare
Set up a soft link
ln -s /var/avoshare /home/avo/share
Then update your config to
[avo-home]
comment = Avo's Home Share
path = /var/avoshare
Encrypted using full disk encryption
Ubuntu's full disk encryption solves your problem. Disadvantage: you need to do that at installation time I believe, so you have to set up your server again.
Encrypted using loopfs
Use an encrypted loopfs for the /var/avoshare folder. Note: most of the commands require root priviledges. Make sure to give avo ownership of the mounted filesystem at the end.
use dd to create a file of size you need. Store the file somewhere, e.g. /var/avoloop
use losetup -e AES /dev/loop0 /var/avoloop
to set up a loopdevice for that file
Format the loopdevice with ext4 using mkfs.ext4 /dev/loop0
You can now mount that loopdevice at /var/avoshare. You need to enter a password for that.
For more convenience, write a script to set up the encrypted loopfs, run that script after you boot the server. The script will use losetup -e AES
and mount
make sure to unmount /var/avoshare before shutting down the machine. Look here for details.