Use only part of external hard drive as storage

I’d like to use only a folder on an external hard drive as the main storage. My understanding is the whole drive’s owner need to set to www-data?

My issue is I mounted the drive as boot with fstab and the owner is set to my account user.

I tried changing the ownership to www-data with chown, running as sudo. But it doesn’t change at all. The drive is mounted as ntfs-3g.

This leads to this error when I pointed the directory to the external hard in the config.php

Your data directory is invalid
Ensure there is a file called ".ocdata" in the root of the data directory.

Cannot create "data" directory
This can usually be fixed by giving the webserver write access to the root directory. See

the data is an exact copy of the default data directory.

Please pointing out what should I do to achieve that. Thanks.