Keeping separate Photos libraries, but sharing one Mac?
My wife and I currently keep our full resolution photos on our respective MacBooks, but this has gotten to be too much data to keep storing on our internal SSDs. So we want to move our personal Photos.app libraries to a shared Mac mini, where they will be stored on one very big external hard drive, which itself is backed up to two Time Machine drives that take turns being offsite backups.
We will most likely use either Photo Stream or ICloud Photo Library to get new photos onto the mini. In either case, I believe this means that we need to run two separate user accounts on the mini, each one staying logged in at all times, with the Photos.app running.
But how do I force both user accounts to reopen automatically at system boot, for example after a power outage? With Photo Stream in particular, failing to reopen the second user account for too long could lead to lost photos. I’m not saying it’s likely, but I can imagine not noticing, or forgetting, when the second account needs to be logged in manually.
Alternatively, is there a way to keep both Photos libraries automatically syncing, from a single user account on the Mac?
(This is in no way about merging two photo libraries into one, a popular topic I find when googling.)