OCP Files NotFoundException after setting datadir

[alfredb]

@Fuuzz

You don’t have permissions to access this file/folder

Well, I assume this is the old story: the volume must be mounted for user www-data.

Setting up help required

I’m not an expert on that topic and I don’t know nor have any raspi. But I know, also from the docs, that the HTTP server user must have r/w access rights for any storage attached to owncloud. And AFAIR, access rights always default to root. A look at this page might help you finding a suitable configuration: