🚀 go-pugleaf

Anyone here use Dropbox?  I recently signed up and am trying to figure 
out how to make use of it and am very confused about how sync works.  I 
googled and googled and can't find any answers.  It's possible I'm not  
entering the right search terms.

Here's my setup.  I have two nix boxes connected to Dropbox.  Call them 
nixA and nixB.  nixA has a symbolic link to a photo directory which 
causes Dropbox to suck up that directory and then nixB sucks down the 
directory.  All is well.  I can add files to that directory and 
everything syncs up perfectly.

I was worried about that symbolic link because it links to a mounted 
drive that should be there but sometimes shit happens and it's not.  I 
worried that Dropbox, upon seeing all the files disappear or getting 
some weird i/o error, would delete the files on their servers and then 
nixB would delete their files.  This would be bad because that directory 
is big and I don't want to retransmit and redownload that directory 
again just because a network mount went haywire.

I'm confused about control over syncing.  I'd like nixB to sync for 
download but not have the ability to make changes (i.e. upload or delete 
locally) to the Dropbox repository but can't find any way to define this 
behaviour.  Anyone who uses rsync should know there are lots of 
different ways of syncing so there should be some way to customize this 
behaviour on Dropbox.

I'd appreciate if anyone knows of a link or can nudge me in the right 
direction.  I have in the past overlooked some rather obvious stuff so 
the answer could be right in front of me.  It has to be because I can't 
be the only one who needs to do this.