trying to ssh from 2018 macbook to mac mini; getting error "pledge: filesystem full" and "shell request failed on channel 0"

Been having a fun day. I upgraded both my mac mini (intel, 2018) and my macbook (intel, 2018) to Monterey and also upgraded openssl and whatever else brew was willing to upgrade. I used to be able to ssh from my macbook to the mac mini with an ssh key I had copied over. Now the spooky stuff:

• my password to authenticate to the mac mini is different from my user's password on the mac mini
• this error message, when I try ssh -Tv [email protected]:

Authenticated to mac.mini.net ([ipaddress]:22) using "password".
debug1: channel 0: new [client-session]
debug1: Entering interactive session.
debug1: pledge: filesystem full
shell request failed on channel 0

• I also get exec failed on channel 0 when I try to copy over an ssh key.

I don't know if I should nuke the whole setup (I need the ssh keys I have to log into other stuff though - I can ssh into other machines without any trouble) - tutorials on safely nuking my ssh setup are welcome if y'all think that is the case. Any advice on what's going on / what to try next would be very helpful.

What version of ssh are you using on the client and the server? You can find out using ssh -V.

Also, for your next step, try ssh -vvv to show all 3 levels of debug mode. It might indicate why it is failing.

BTW, the debug1: pledge: filesystem full message actually has to do with the HostKeys in the UserKnownHostsFile. See UpdateHostKeys: https://man7.org/linux/man-pages/man5/ssh_config.5.html and client_loop() https://fossies.org/linux/openssh/clientloop.c.